Download SoE 08 Part 4.3 Inland Waters

PART FOUR
STATE OF THE ENVIRONMENT
4.3 INLAND WATERS
Key Findings
• Direct pressures to inland waters include the construction
of dams, flow regulation and water harvesting; draining of
wetlands; desnagging; channelisation and the construction of
levees.
• Clearing of almost half of Victoria’s native vegetation and
associated land use changes have had negative impacts on
inland waters including loss of riparian vegetation, altered
hydrology, erosion, and increased loads of sediments and
contaminants such as salt, nitrogen and phosphorus.
• The 2004 Index of Stream Condition assessment reported
that only 21% of major rivers and tributaries in Victoria were in
good or excellent condition. Almost half the basins in Victoria
have less than 10% of major rivers and tributaries in good or
excellent condition.
• The extent of degradation indicated by the 2004 Index of
Stream Condition assessment was present before the drought,
but low streamflows combined with current levels of extraction
have compounded pressures on inland waters since this
assessment.
• The Sustainable Rivers Audit reported that 9 out of 10
Victorians basins in the Murray Darling Basin were in very poor
ecological health, and one basin was in poor ecological health.
• In over half the river basins in Victoria, less than 20% of major
rivers and tributaries have flow regimes in good condition.
Changes to low flow events were most widespread, causing
numerous pressures ranging from changed breeding
conditions to poor water quality. Lack of flooding threatens the
existence of tens of thousands of hectares of River Red Gum
Forests.
• In 2004, just 6% of major rivers and tributaries had in-stream
habitat in good condition based on the presence of large
woody habitat, bank stability and barriers to fish passage.
• In 2004, 14% of major rivers and tributaries had riparian
vegetation in good condition. Uncontrolled stock access to
riparian zones continues to be the major pressure on riparian
vegetation statewide.
• By 1994, 37% of naturally occurring wetland area had
been lost, mainly due to drainage. A more recent statewide
assessment has not been conducted.
• In 2005, water quality objectives for salinity were met at 68%
of sites across Victoria, and objectives for total nitrogen, total
phosphorus, and turbidity were met at less than half the sites
monitored.
• Many species dependent on inland waters are now considered
threatened, including 21 freshwater and estuarine fish species,
11 frog species and 29 species of waterbirds.
• In 2004, macro-invertebrate communities were in good
condition across almost half of the major rivers and tributaries
assessed.
• The total index of abundance for waterbirds in eastern Australia
has shown a declining trend over past decades, with 2007
having the second-lowest abundance on record.
• Commitments to provide environmental water were qualified
in 40 locations across Victoria in 2006-07, as part of drought
contingency measures.
• Under climate change, streamflow is projected to decrease
by up to 50% across much of Victoria by 2070. The present
degraded state of many inland waters increases the challenge
of mitigating the environmental impacts associated with climate
change.
• Victoria’s inland waters have inherent value, and contribute
greatly to the broader environment, community and individual
human health. Inland waters provide valuable ecosystem
services such as drinking water, cycling of nutrients and
maintenance of biodiversity, as well as recreational and cultural
opportunities. Many markets fail to protect and may even
encourage the degradation of these services, even though they
support healthy economies and communities.
• Incremental degradation due to cumulative catchment and
instream impacts remains an ongoing challenge. The expense
and difficulty of rehabilitation highlights the importance of
protecting high value areas.
• Over the past two decades, and particularly in the last decade,
there has been increasing knowledge; investment; integration
of management; on ground capacity and awareness to drive
improvements in the condition of inland waters. In the context
of ongoing drought and likely climate change the future
health of many inland waters is uncertain and further action is
necessary.
IW0 Introduction
Victoria’s inland water assets
Victoria’s inland waters (rivers, streams,
wetlands and groundwater) have inherent
value and contribute greatly to the
broader environment, communities and
their economies, and individual human
health. Examples of these values include
drinking water, biodiversity, nutrient cycling
and water purification, recreation and
agricultural productivity.
Water systems – inland waters, estuarine
or marine - are all part of and therefore
connected through the water cycle. Inland
waters are also intimately connected with
the land, as all land is part of a catchment,
and all catchments have a receiving
water body1. When these systems are
functioning healthily, the ecology of inland
waters has both the capacity to resist
disturbances and recover from them.
However, if an ecosystem is acutely
disturbed beyond the threshold of a
key variable, e.g. rate of groundwater
recharge, it will behave differently,
often with undesirable and unforeseen
consequences. Once a threshold
has been crossed it is difficult, if
not impossible, to rehabilitate the
system. Rising groundwater tables,
salinisation, landscape-scale erosion and
sedimentation, persistent cyanobacterial
blooms and species extinction are all
signs that resilience has been lost, and
potentially irreversible changes to inland
waters have occurred.
Over the past two decades, and
particularly in the last decade, there has
been an increasing effort to improve the
condition of inland waters. The benefits
of management actions have been
demonstrated in many individual and
even regional cases, but in the context
of ongoing drought and climate change
the future health of many inland waters is
uncertain and further action is necessary.
The expense and difficulty of rehabilitation
highlights the importance of protecting
existing areas of high value. Incremental
degradation due to cumulative catchment
and in-stream impacts remains an
ongoing challenge.
The issues reported in this section provide
a window into the current condition of
Victoria’s inland waters. Major rivers and
tributaries receive most attention as these
are most comprehensively monitored.
Specific indicators for groundwater and
wetlands are also reported.
The term ‘inland waters’ is used inclusively
to cover rivers and streams, wetlands,
groundwater, habitat linkages such as
riparian vegetation and floodplains, their
ecology and associated ecosystem
processes. The term ‘wetlands’ includes
coastal wetlands. The terms ‘rivers and
streams’ are used interchangeably and are
inclusive of associated habitats, ecology
and ecosystem processes. Victoria’s rivers
and river basin are shown above in Figure
IW0.1.
Objectives
• Maintain and improve the condition of
inland waters, assigning the highest
priorities to those water systems
with the highest environmental and
community values.
• Maintain the capacity of inland waters
to provide ecosystem services that
support agreed environmental, social
and economic values.
Pressures
Inland waters have been transformed
into a complex and extensive system
for harvesting, storing, transporting and
controlling water. Dams are part of this
system, as they store water so it can be
harvested or released at a later time. In
western Victoria and in basins north of the
Divide, the drive for State development in
an inherently variable climate has resulted
in the extensive use of irrigation to support
agriculture, widespread construction of
storages and the use of river channels
to convey water long distances from
where it is stored (see Part 3.2: Water
Resources). Large proportions of the
total surface water in several basins are
extracted for consumption, particularly in
dry years. Flow regimes have been heavily
modified in these rivers, placing pressure
on floodplain ecosytems including River
Red Gum forests; and in most major rivers
throughout Victoria.
Extensive areas of valley floors throughout
the State, for example the Latrobe valley,
were originally wetland: swampy areas of
tea-tree, or chains of ponds which were
reclaimed for agriculture by digging drains
or ploughing. These drains often eroded
into gullies. To reduce the duration and
frequency of flooding, larger streams
were ‘channelised’ to convey water more
rapidly, by desnagging, straightening, and
the construction of artificial levees.
Lowland areas, particularly those near
past or current population centres such
as Melbourne, have been most affected
by changes to the movement of water
through the catchment. Both bed and
bank stabilisation works, and stream
clearing works, tend to increase from west
to east across Victoria3. Areas with high
concentrations of stream clearing works
include the lower reaches of the north
eastern basins (Upper Murray, Kiewa,
Goulburn and Ovens) and the south
eastern Yarra, Bunyip, Thomson, Latrobe
and South Gippsland Basins (see Figure
IW2.7).
A wave of goldrushes in the nineteenth
century, and mechanical dredging for
alluvial gold which was widespread across
Victoria until the late 1980s, affected
many rivers and extended into upland
areas which have remained otherwise
undeveloped. As a result the physical
condition of the river channels has
degraded, in some cases irreversibly, even
when the catchment remains substantially
intact.
The ecology of a stream is related to
the condition of the catchment4. About
half of Victoria’s native vegetation has
been cleared, including 80% of the
original cover on privately owned land.
Land clearing has resulted in loss and
degradation of riparian vegetation (see
IW3 Riparian Vegetation) and accelerated
erosion and sedimentation (see IW2
In-stream and wetland habitat, IW4 Water
Quality).
Clearing of vegetation also has significant
impacts on the volume and timing of
water delivered to inland waters and
has generally increased recharge of
groundwater leading to salinisation (see
Part 4.2: Land and Biodiversity)5. Irrigation
has amplified this change, resulting in
shallow watertables, waterlogging and
increasing salinity (see IW4 Water Quality,
State), in approximately 140,000 ha of
land in the irrigation districts of northern
Victoria6. The threat currently posed by
salinity has been moderated by improved
management practices and rainfall deficits
over the past 11 years have but it remains
latent.
Pollutants originating in catchments, such
as nutrients in fertilisers, domestic and
industrial wastewaters, and toxicants from
roads, agriculture and industry also place
pressure on inland waters.
The extensive modification and
fragmentation of inland waters has aided
the spread of invasive species, which are
now difficult to control (see IW3 Riparian
Vegetation, IW5 Aquatic Fauna). Victoria’s
Flora and Fauna Guarantee Act 1988 lists
eight processes as potentially threatening
to inland waters (see IW5 Aquatic Fauna,
Pressures).
Drought, combined with current levels
of extraction compounds pressures on
flow regimes, and has implications for
all issues subsequently discussed in this
part of the report. Climate change, which
is already influencing temperatures and
rainfall patterns, is another compounding
pressure and will further increase
competition for water resources. Climate
change is a serious risk to the health of
inland waters (see IW6 Impacts of Climate
Change on Inland Waters).
Overall condition
Almost all rivers and catchments in
Victoria, and almost all larger streams,
have been modified to some degree.
Varying levels of information on current
condition are available for the different
components of Victoria’s inland waters.
The most comprehensive condition
assessments are available for major
rivers and streams, which are assessed
every five years using the Index of Stream
Condition (ISC). Two assessments (1999
and 2004) have been conducted, with the
next due to occur in 2009.
The 2004 ISC assessment reported that
about 21% of major rivers and tributaries
in Victoria were in good or excellent
condition, 47% were in moderate condition
and 32% were in poor to very poor
condition (see Figure IW0.2, also see
Management Responses, Index of Stream
Condition). The river basins in poorest
condition were mostly in the western
half of Victoria, whereas the basins in
best condition were in eastern Victoria,
particularly in the highland forested
areas which have proved unsuitable
for conventional agriculture (see Figure
IW0.3). In some basins, such as the
Thomson, the upper reaches are in good
condition, whereas the lower reaches
have been highly modified, giving a lower
overall score for the basin. Almost half
the basins in Victoria have less than 10%
of major rivers and tributaries in good or
excellent condition.
No major overall changes in condition
were identified between the ISC
assessment in 2004 and the first
assessment in 1999, which occurred at
the beginning of the current drought7. The
degradation of inland waters reported in
the 2004 ISC is therefore not due to the
current drought, having existed prior to it.
Drought and current levels of extraction
have compounded existing pressures
on rivers and streams since 2004, as the
scarcity of water has increased over time.
Additional information on ecological
condition of Victorian rivers of the Murray
Darling Basin is available through the
Sustainable Rivers Audit, another method
for assessing the ecological health of
inland water which is being applied to the
Murray Darling Basin.
The first assessment consisted of
Hydrology, Fish and Macro-invertebrate
themes, based on data collected between
2004 and 2007. The Audit divides the
Basin into valleys which, in Victoria, do
not always coincide with the basins used
as the main spatial unit in this report
(for example, the Mitta Mitta Valley is
considered independently). Valleys are
further split into zones according to
altitude: lowland, slopes, upland and
montane.
Nine out of 10 Victorian Valleys in the
Murray Darling Basin were in very poor
ecological health, and one Valley - the
Ovens - was in poor ecological health. The
Goulburn Valley was considered the least
healthy valley in the Murray Darling Basin,
along with the Murrumbidgee in New
south Wales. The ‘upland’ and ‘montane’
zones of the Ovens valley, and the ‘Slopes’
zone of the Broken Valley, which were
in moderate condition, were the highest
rated zones in Victoria. The condition of
remaining zones ranges from poor to
extremely poor.
Across Victoria, an estimated 191,000
ha of natural wetlands, some 37% of
the original wetland area, were lost by
1994, according to a statewide inventory
conducted in that year9. Over 90% of the
wetland area lost was on private land. The
change in extent of wetlands since 1994
has not been assessed on a statewide
basis. An Index of Wetland Condition
assessment tool has been developed and
is currently being finalised.
The condition of groundwater has
historically been observed through
levels and quality. Groundwater levels
are at record low levels in 12 of the 24
most heavily developed groundwater
management units due to lack of recharge
and consumptive pressure (see Part 3.2:
Water Resources). Groundwater quality, in
the context of environmental condition, is
linked to salinisation which has occurred
throughout western Victoria (see Part 4.2:
Land and Biodiversity, Indicator LB29
Area of salt affected land). An index for
assessing the condition of groundwater
dependent ecosystems is currently being
developed.
Due to lack of information, the condition
of small streams, anabranch networks
and floodplain connections has not been
included in this Report. These waterways
comprise 93% of the total stream length
in Victoria. Small streams are important
for water quality, as they filter catchment
inputs and aid nutrient cycling. Anabranch
networks convey a large proportion of the
total flow of lowland rivers. About 34% of
the total stream length is in largely intact
landscapes and the remaining two-thirds
are in fragmented landscapes (see Part
4.2 Land and Biodiversity, LB1 Vegetation
loss and modification). Although streams
in intact landscapes are more likely
to be in better condition than those in
fragmented landscapes, condition is also
determined by factors such as upstream
condition and management activities.
The extent of clearing, wetland drainage
and stream modification works
emphasises the importance of areas
that are relatively unaltered. Victoria’s
network of parks, which cover 14% of the
State, are important refuges that protect
remnant vegetation and include important
catchment areas10.
Management responses
Management of inland waters in Victoria
is administered by all jurisdictional
levels. Commonwealth, State and
local governments have input through
legislation, policy and funding decisions
and implementation of planning
provisions. As described in Part 3.2: Water
Resources, the Victorian Government
retains the overall right to the use, flow
and control of water resources, including
surface, ground, storm and recycled
water12.
Victoria is divided into 10 catchment
management authority (CMA) regions (see
Figure IW0.4). The CMAs were established
in 1997 under the Catchment and Land
Protection Act 1994 and their structure
is described in detail in the Victorian
Catchment Management Council’s
Catchment Condition Report13. The role of
each CMA is to facilitate and coordinate
integrated catchment management
relating to land, biodiversity and water
resources within each catchment.
CMAs were assigned the role of caretakers
of river health through the Victorian River
Health Strategy (2002) and subsequently
gained responsibility for managing the
Environmental Water Reserve15. Waterway
management responsibilities include
responsibility for the co-ordination and
management of floodplains; stormwater
runoff and pollution; rural drainage
(including regional drainage schemes);
water quality and nutrient management;
water supply catchment protection;
wetlands; restoration of degraded
waterways; and Crown frontages and
heritage rivers outside of national parks16.
Until recently the Murray-Darling Basin
was managed by the Murray Darling Basin
Commission through the Murray-Darling
Basin Initiative, under the Murray-Darling
Basin Agreement (1992). Six governments,
and many departments and agencies,
were involved in the Agreement. An
Intergovernmental Agreement on MurrayDarling Basin Reform was signed on July
3, 2008, which transfers the powers and
functions of the Murray Darling Basin
Commission to a new Murray Darling
Basin Authority. A key task for the Authority
is the preparation of a new Basin Plan,
to be completed by 2011. The Authority
reports to the Commonwealth Government
Minister for Climate Change and Water17.
In Victoria, 10 out of 29 river basins are
part of the Murray-Darling Basin: Mallee,
Wimmera, Avoca, Loddon, Campaspe,
Goulburn, Broken, Ovens, Kiewa and
Upper Murray.
At the national level, the National Water
Initiative (2004) is working towards
a nationally compatible system of
managing surface water and groundwater
resources18.
The main over-arching policies,
strategies and legislation which guide
the management of inland waters are
summarised below.
Our Water Our Future (2004)
Our Water Our Future is the Victorian
Government’s main policy for managing
water resources. Major initiatives include
a revised water allocation framework, the
creation of an environmental water reserve
(EWR), a policy framework for urban
water management and water pricing.
See Part 3.2: Water Resources for more
information.
One of the guiding principles of Our Water
Our Future is that a healthy economy and
society is based on a healthy environment.
Our Water Our Future commits the
Government to significantly improving the
health of Victoria’s rivers, floodplains and
estuaries to ensure they are capable of
delivering a wide range of services to the
community19. This goal is to be achieved
by 2010.
Regional sustainable water strategies
Four regional strategies are being
developed for the achievement of
sustainable water use in Victoria, including
actions to improve river health, over
the next 50 years (see Part 3.2: Water
Resources).
State Environment Protection Policy
(Waters of Victoria)
The State Environment Protection Policy
Waters of Victoria (SEPP WoV) sets out
the statutory framework for the protection
of Victoria’s freshwater systems, and is
administered by Victoria’s Environment
Protection Authority (EPA), under the
Environment Protection Act 1970 (see
also IW4 Water Quality, Management
Responses). The SEPP prescribes20:
• Beneficial uses, which are the uses and
values of the water environment that
the community and government want to
protect.
• The objectives and indicators which
describe the environmental quality
required to protect beneficial uses.
• An attainment program that guides
the restoration and protection of water
environments so environmental quality
objectives are met and beneficial uses
protected.
Victorian River Health Strategy (VRHS)
The VRHS, administered by the
Department of Sustainability and
Environment, is the Victorian
Government’s framework for improving the
health of rivers, floodplains and estuaries.
The framework aims to protect high-value
rivers, maintain ecologically healthy rivers
and achieve an overall improvement in the
environmental condition of the rest21.
Victoria’s Biodiversity Strategy (1997)
This strategy fulfils commitments in the
National Strategy for the Conservation
of Australia’s Biological Diversity (1996)
and requirements under Victoria’s Flora
and Fauna Guarantee Act 1988. Actions
for the management of wetlands are also
prescribed in this strategy. A new policy
document for biodiversity is planned for
release in 2009. These documents are
described in more detail in Part 4.2: Land
and Biodiversity.
Response Name
Victorian River Health Program
Responsible Authority
Department of Sustainability and
Environment
Response Type
Policy/strategy
The Victorian River Health Program
was established in 2002 with the aim of
restoring Victoria’s rivers. The program’s
overall framework, objectives and targets
were established through the Victorian
River Health Strategy (2002) and Our Water
Our Future (2004).
This framework is supported by
regional river health strategies, which
each form part of the corresponding
regional catchment strategy (see Part
4.2: Land and Biodiversity). Regional
river health strategies address fisheries
management plans, flow, water quality,
waterways management and floodplain
management22.
Through the Victorian River Health
Program, the State Government invested
$100m between 2004 and 2008) in
river health, with a focus on protecting
and rehabilitating high-priority areas. A
monitoring and research program, of
which the ISC is a central tool, aims to
facilitate adaptive management and the
monitoring of environmental condition.
The achievements of the program are
expressed in terms of progress towards
statewide targets, which are discussed in
the Management Responses below. The
stages of the River Health Program are
shown in Figure IW0.5.
Recommendation
IW0.1 Implement consistent statewide
reporting and data management of
works implementation and condition
assessment for rivers, wetlands
and groundwater, aggregated at
the basin or CMA level, to show the
impact of management responses on
environmental condition.
Response Name
Index of Stream Condition
Responsible Authority
Department of Sustainability and
Environment
Response Type
Monitoring program
The Index of Stream Condition (ISC) is
an integrated, statewide benchmarking
of environmental condition, implemented
by the Department of Sustainability and
Environment (DSE) and the catchment
management authorities (CMAs). Most of
the indicators in this section are based on
the underlying data from the 2004 ISC.
The health of Victorian rivers is assessed
every five years. The ISC considers five
key aspects of river health for over 1,040
individual reaches. The five aspects
assessed are: changes in hydrology
(amount, timing and duration of flow);
water quality; streamside zone (riparian
vegetation); physical form (bank condition
and in-stream habitat); and aquatic life.
These aspects are rated by comparing
the observed condition measured in the
field, with a natural benchmark condition
established through a desktop analysis.
Benchmark conditions can be difficult
to establish, particularly for reaches
of lowland rivers. Where there is little
difference between the observed and
the benchmark conditions, the site is
considered to be in good condition.
A reach is a section of river between
10 km and 30 km long with relatively
homogeneous flow, vegetation and
landscape characteristics24.
Data collected at the reach scale are
aggregated to provide a snapshot of river
health at a basin or statewide scale. Sites
are randomly selected for assessment. In
some basins, results aggregated to the
basin scale (which is used extensively in
this report) may be weighted in favour of
upland sites, which tend to be in better
condition. This is simply because in some
basins there is a greater length of upland
rivers and streams considered by the ISC,
relative to lowland rivers and streams. An
assessment of river health using the ISC
was first conducted in 1999, followed by
an assessment with an improved version
in 200425.
The capacity to measure integrated river
condition statewide is crucial to effective
adaptive management at a time of
considerable uncertainty and to assess
the long-term effectiveness of the Victorian
River Health Program. On the other hand,
it is necessary to ensure that on-ground
works are not driven just by the ISC, which
can only provide a partial view of river
health.
An ongoing challenge is the inclusion
of new knowledge and measurement
techniques, while still enabling comparison
between assessments over time. This may
require the development of new indicators
to provide a more sensitive assessment of
the forces driving degradation.
Response Name
Ramsar Convention on Wetlands
Responsible Authority
Department of Environment, Water,
Heritage and the Arts/Department of
Sustainability and Environment
Response Type
International Agreement
The Ramsar Convention on Wetlands
(1971) promotes the conservation, repair
and wise (i.e. sustainable) use of all
wetlands, with particular emphasis on
sites listed as ‘Wetlands of International
Importance’, also known as Ramsar sites26
(see Figure IW2.3).
In Victoria, 10 wetlands were designated
Ramsar sites in 1982, with the EdithvaleSeaford wetlands being added in 200127.
A Strategic Directions Statement (2002)
provides a framework for the management
of Ramsar sites28. Management plans
for each of the sites were prepared in
2003. In 2005, an Ecological Character
Description Framework was developed
by DSE to guide the development of
detailed ecological character descriptions
for each site29 and used to describe the
Barmah forest. A new national framework
for developing ecological character
descriptions of Ramsar wetlands
was published in June 2008 by the
Commonwealth Government30.
While the designation of sites under the
Ramsar Convention and the preparation
of management strategies are important
steps, continued active management of
these sites is necessary to respond to
pressures on environmental condition.
Ramsar sites, such as Lake Albacutya,
Western District Lakes, Gunbower Forest,
Barmah Forest and Gippsland Lakes,
have been allowed to degrade. Funding
for the management programs is largely
provided by the Commonwealth and other
land managers including Melbourne Water
Corporation, with limited state funding
available.
Recommendation
IW0.2 The Victorian and Commonwealth
Governments should strengthen
and improve management regimes
of Ramsar wetlands, to ensure the
obligations of the Convention are met.
Evaluation of responses
The past decade has seen the
implementation of the policy framework
and delivery mechanisms for an integrated
approach to improving the condition
of inland waters. Through the Victorian
River Health Program, much work has
been done to halt further degradation
in condition of Victoria’s rivers. A major
challenge is implementing policies and
strategies as they were intended, to
reverse the degradation.
There have been significant advances
in the knowledge and understanding
which underpins the management of
inland waters since the mid-1990s.
Examples include integrated assessments
of environmental condition such as
the Index of Stream Condition and the
Rapid Biological Assessment technique
developed by the EPA, the importance
of woody habitat, nutrient cycling and
transport, and the management of algal
blooms. Continued effort to develop
good science and proactive, transparent,
inclusive decision-making is needed to
improve the condition of inland waters.
The assessment of wetland condition
has lagged behind that of rivers and
streams. This is being addressed through
the Index of Wetland Condition which,
when fully tested, must be implemented
statewide. Similarly, the Index of
Groundwater Condition will address the
lag in monitoring and assessment of
groundwater-dependent ecosystems.
The implementation of the National
Groundwater Action Plan (2007) should
also assist in rectifying knowledge gaps
relating to groundwater31.
Many pressures on inland waters
remain, including the legacy of historic
management practices, which have been
exacerbated by the low streamflows and
high temperatures of the past decade.
In many rivers and aquifers the current
EWR is inadequate and vulnerable,
placing environmental values at risk32.
During times of low streamflow, the
water allocation system also reduces
environmental flows more than it reduces
water for consumptive uses. Lack of water,
and increased competition for that which
remains, has constrained initiatives to
improve environmental flows. (see IW1
Flow regimes). The scarcity of water has
dramatically increased public awareness
of its management.
Climate change poses a serious threat
to inland waters. Due to uncertainty
over what may happen, management
responses consider multiple scenarios,
with an emphasis on risk management
and adaptive management frameworks.
The Central Region Sustainable Water
Strategy and the Victorian River Health
Strategy both use adaptive management
frameworks to enable the incorporation
of new information into management
decisions.
Small streams and anabranch networks
need to be factored into management
plans at some level. The sheer length
of these networks has to date made
monitoring impractical, but emerging
technologies may allow the development
of metrics which will assist condition
assessment and management. A watching
brief should therefore be placed on these
technologies.
Incorporating the value of ecosystem
services into markets is crucial to
maintaining and improving the condition of
inland waters. A project to address some
current knowledge gaps is underway
(‘Ecosystem Services: Valuing Improved
River Health’ managed by DSE) but more
effort is urgently required to address
market failures. Market instruments
for allocating resources to restoration
works to maintain ecosystem services
have also been successfully trialled (e.g.
RiverTender, see section IW3.7).
Recommendations
IW0.3 The Victorian Government should
reinforce its commitment to significantly
improving the health of Victoria’s rivers,
floodplains and estuaries by 2010 as set
out in Our Water Our Future, and other
inter-jurisdictional river health initiatives
IW0.4 Ecosystem services should be
recognised as a component of the value
of land, so that landholders can treat
ecosystem services as an alternative
source of income. Knowledge of the
interaction between ecosystems and
the services they provide to human
settlements should be improved.
IW0.5 Institutional arrangements of
catchment management authorities
and water corporations should be
reviewed with the goal of integrating
water management to enable better
delivery of water for the environment,
and adaptation to climate change
IW0.6 The Victorian Government
should review reporting cycles of Index
of Stream, Wetland and Groundwater
condition indexes, and the State
Wetland Inventory, to facilitate better
integration with Victorian Catchment
Management Council and State of
Environment reporting.
IW0.7 Implement the Indexes of
Wetland Condition and Groundwater
Condition on a statewide basis as soon
as possible, to enable more accurate
reporting to inform decision making
For further information
Index of Stream Condition
http://www.vicwaterdata.net/vicwaterdata/
data_warehouse_content.aspx?option=5
Victorian Catchment Condition Report:
http://www.vcmc.vic.gov.au
Victorian Government water and river
health programs and publications
http://www.dse.vic.gov.au/dse/wcmn202.
nsf/Home+Page/592E2077307FBB0CCA2
56FE100095CDD?open
Sustainable Rivers Audit Report 1
http://www.mdbc.gov.au/SRA/river_health_
check_-_sra_report_one
IW1 Flow Regimes
Key findings
• A flow regime is a specific combination
of the timing, size and duration of flow
events. It is a key driver of river and
floodplain wetland ecosystems.
• The main pressures on flow regimes
are the presence of dams and other
barriers; regulation of flow; extraction
of water for consumption; channel
modification; and changes in land
use. Drought has compounded these
pressures over the past 11 years; and
they are likely to be compounded by
climate change in future.
• In the past four years, over 75%
of the total flow was harvested for
consumptive use from a quarter of
Victoria’s river basins. During times of
low streamflow, the water allocation
system reduces environmental
flows more than it reduces water for
consumptive uses.
• Serious rainfall deficiencies over the
past 11 years have reduced inflows
to storages 30–60% below long-term
averages. Water scarcity has been
statewide in extent, and has deepened
over time, with inflows to the Murray and
Melbourne storages reaching record
lows in 2006.
• In over half the river basins in Victoria,
less than 20% of rivers have flow
regimes in good condition. Changes to
low flow events are most widespread,
resulting in a number of pressures
from changed breeding and spawning
conditions to poor water quality.
• Due to river regulation and overextraction
compounded by drought,
many tens of thousands of hectares of
River Red Gum forests and wetlands
in northern Victoria are highly stressed.
Without adequate flooding in the near
future they may be lost, requiring
centuries to recover.
• Water availability will be cumulatively
reduced by climate change and
catchment processes such as forests
regenerating after bushfires; the legacy
of historic groundwater extraction; small
unlicensed domestic and stock farm
dams; and plantation forestry.
• In many rivers and aquifers the
current environmental water reserve
(EWR) is inadequate and vulnerable,
placing environmental values at risk.
Commitments to provide environmental
water were qualified in 40 locations
across Victoria in 2006-07, as part of
drought contingency measures.
• Significant improvements in the way
water is managed for the environment
have occurred in the past decade,
including the recognition of the
environment’s right to water in the
allocation framework, commitments
to improve flow regimes; better
water accounting and scientific
understanding.
Description
The flow regime is a key driver of river
and floodplain wetland ecosystems33.
Each river has its own flow regime, with a
specific pattern of changes in the season,
timing, frequency, volume, rates of rise
and fall, and duration of flows. These
characteristics influence the physical
nature of river channels, biodiversity, and
the key processes that sustain the aquatic
ecosystem and the ecosystem services
that inland waters provide34. Aquatic plant
and animal species have evolved life
histories directly in response to the natural
flow regimes35. Altering flow regimes may
change patterns of habitat connectivity
essential to the population viability of
many freshwater species and facilitate the
invasion of exotic species36.
Rivers and groundwater are connected,
and most Australian rivers derive
flow from groundwater most of the
time37. Groundwater level regimes are
important for maintaining the health of
rivers, floodplain wetlands and other
groundwater-dependent ecosystems.
These links are yet to be fully integrated
into policy and management processes.
Two centuries of works designed to control
and change the direction and speed of
water as it moves through the landscape
has extensively degraded flow regimes
and reduced the volume of water available
to the environment. Direct modifications to
river channels and catchment include the
construction of dams, extraction of water,
straightening of channels and urbanisation
of catchments, and have altered the
speed at which water moves through the
landscape. Indirect pressures such as
the clearing of vegetation, agriculture,
groundwater extraction, farm dams,
plantation forestry and re-growth following
bushfires have also altered catchment
hydrology.
Serious rainfall deficiencies over the past
11 years have reduced inflows to storages
30–60% below long-term averages.
Water scarcity has been statewide in
extent, and has increased over time, with
inflows to the Murray and Melbourne
storages reaching record lows in 2006.
As competition for water resources has
increased, the cumulative impacts of water
harvesting have become more acute.
These pressures have been compounded
in the past decade by streamflows well
below the long-term average (see Part 3.2:
Water Resources) and they are expected
to intensify with climate change38.
Objectives
• Protect natural water regimes and where
these have been modified, retain or
reinstate as many of the features of the
natural water regime as possible.
• Manage wetlands, rivers and
groundwater systems as integrated
systems to ensure adequate flow to
support healthy waterways.
State
The indicators in this section relate to the
condition of major rivers and tributaries.
The term ‘flow regimes’ is used in
this context, but is inclusive of links to
groundwater and wetlands. Trends in
regional groundwater levels are also
presented. Assessments of groundwaterdependent
ecosystems are currently being
conducted and should be included in
future State of Environment reporting.
There is an urgent need for an agreed
and consistent classification system for
determining the flow regimes of wetlands
in Victoria39, as the determination of the
water requirement for wetlands is an
essential requirement for management.
The water requirements of all River Murray
icon sites have been determined by the
respective jurisdictions under The Living
Murray program. The water requirements
of other important wetlands in the Victorian
component of the Murray-Darling basin
are currently being documented.
Indicator IW1 Condition of flow regimes
of major rivers and tributaries
In 2004, flow regimes were in good
condition for 24% of the total reach-length
assessed, with a further 45% in moderate
condition and 31% in poor condition
(Figures IW1.1 and IW1.3). The Mitchell,
Upper Murray and East Gippsland basins
had flow regimes in best condition, with
80% or more of reach-length with flow
regimes rated as ‘good’. This is because
the Mitchell and East Gippsland basins
have no major dams, while most the
storages in Upper Murray are downstream
of the reaches assessed. The Millicent
Coast basin had flow regimes in good
condition, but there is very little flow in this
basin. Flow regimes in the main part of the
Snowy River has been severely modified
by the diversion of up to 99% of flow in
NSW as part of the Snowy Mountains
Hydro-electric Scheme40. However, while
the main stem of the Snowy River has
lost the spring flood which was critical to
its ecological integrity, the tributaries of
the Snowy River have largely unmodified
catchments and stream beds41, and this
has protected the condition of many of
the river’s reaches. Four basins (Mallee,
Maribyrnong, Hopkins and Portland
Coast) had no assessed reaches with flow
regimes in good condition. The Mallee
basin is in poor condition because the
only river assessed for this basin, the River
Murray, is heavily regulated. Overall, 16
out of 29 basins had no more than 20%
of reach length with flow regimes in good
condition (see Figure IW1.3). Flow regimes
are generally worse below major storages
and water diversion points.
The reaches assessed were most altered
from natural flow regimes in summer, with
low flows being the most modified flow
component (see Figure IW1.3). Of the
reaches in poor condition, about 85% are
most altered from their natural condition
in summer, and the most affected
component is low flows. An example of
this is seen in regulated rivers used to
supply water for irrigation, such as the
Macalister and Goulburn Rivers, where
water is sent from storage downstream
for irrigation during the summer months,
creating flows that are much higher than
would naturally be seen at that time of year.
The remaining 15% of reaches in poor
condition are most altered from their
natural condition during winter. In these
cases the components of the flow regime
most affected are low flows and high
flows. This often reflects the effects of
major storages, which capture most
of the winter high flows and therefore
significantly reduce flow downstream
(See Part 3.2: Water Resources for more
information).
Of the reaches with flow regimes in
moderate condition, 93% are more altered
from their natural condition in summer
than winter with low flows again being the
most modified component of their natural
flow regime. The remaining 7% of reaches
in moderate condition are most altered in
winter through modifications to both their
low-flow and high-flow components.
Of the river reaches with flow regimes
in good condition, only 11% are
considered in excellent condition, with no
modifications to their natural flow regime.
About 84% of reaches in good condition
were most altered in summer, with low
flows being the most affected component.
The remaining 7% of reaches in good
condition were most altered in winter,
with high flows being the most affected
component.
Indicator IW2 Trends in regional
groundwater levels
Long term trends in regional groundwater
levels across Victoria have generally
remained stable over the past five years46.
Nine groundwater management units, out
of a total of 67, were identified as having
declining trends over the five years to
2006-07 (see Part 3.2: Water Resources).
Groundwater levels and trends for August
2008 show more widespread decreasing
trends, due to the continuing lack of
recharge and increased consumptive
pressure47. Groundwater levels in 12 water
supply protection areas were at their
lowest on record.
Pressures
The main pressures on flow regimes are
the presence of dams and other barriers;
regulation of flow; extraction of water for
consumption; channel modification; and
changes in land use. These pressures
affect groundwater and wetlands, as
well as rivers. Over the past 11 years
drought has compounded pressures on
flow regimes, and climate change is also
likely to place pressure on flow regimes in
future (see Part 4.1: Atmosphere, Climate
Change).
Indicator IW3 Surface water harvested for
consumptive use as a percentage of the
total water in the basin
Current levels of water consumption
increase the pressure exerted by low
streamflow on the biota of inland waters,
despite their adaptation to high variability.
In a quarter of Victoria’s river basins, over
75% of the total annual flow was harvested
the past four years (2003–04 to 2006–07).
The basins experiencing the greatest
reduction in streamflow over this time also
recorded the highest percentage of water
harvested. This indicator is reported in Part
3.2: Water Resources, Pressures on the
Environment.
Recommendation
IW1.1 Government should address
the disproportionate reduction in water
remaining in basins during times of
low streamflow, which results from the
current system of bulk entitlements
defined as a volumetric share of the
resource.
Regulation of flow
Major storages, weirs and levees are the
most common cause of alteration to flow
regimes48. At least one major on-stream
storage occurs in 65% of Victoria’s river
basins (19 out of 29)i. Storages often result
in large decreases in flow immediately
downstream. For example, there is a 95%
reduction in flow immediately downstream
of the Upper Yarra Dam49. The release
of high-velocity water during weir and
dam operation scour away and weaken
riverbanks, resulting in bank slumping and
instability.
In irrigation areas, flow regimes are
dictated by the needs of consumers rather
than environmental requirements as rivers
are used to convey water released from
storages to consumers. Water is also
released from storages for hydro-electricity
generation.
Levee banks are constructed to reduce
flooding and protect property from
flooding but they typically isolate the river from the floodplain (locations of levees are shown in Figure IW2.6).
Extraction of groundwater
Where aquifers are connected to
surface waters, harvesting of water
from groundwater bores, as well as the
excessive extraction of surface water,
can lower groundwater levels, leading to
a range of environmental impacts (see
Part 3.2: Water Resources, Groundwater,
Pressures on the Environment). On
the other hand, land use changes for
agriculture have generally increased
recharge to groundwater50 (see Part 4.2
Land and Biodiversity).
Altered catchment hydrology
Flow regimes are cumulatively affected
by changes to runoff and groundwater
recharge throughout the catchment.
Approximately half of Victoria’s native
vegetation has been cleared, including
80% of the cover on private land (see
Part 4.2 Land and Biodiversity). This
has generally increased recharge
to groundwater, which has placed
pressure on terrestrial systems as well
as inland waters (see Part 4.2: Land and
Biodiversity, LB6 Salinity). In irrigation
areas, the extra water added to irrigated
land has accelerated the increase in
groundwater levels. The catchment
response to rainfall has also been
modified, leading to changed groundwater
conditions, an increase in surface water
run-off and, as a consequence, changed
flow regimes51.
A major pressure is the proliferation
of farm dams, which have increased
in number from 300,000 in 1988 to
355,000 in 2004–0552 (see Part 3.2: Water
Resources). While farm dams do not
regulate flow directly, by intercepting runoff
they increase evaporation and reduce
streamflow, thereby affecting flow regimes.
Farm dams capture a higher proportion
of runoff during summer, leading to lower
flow and longer low-flow periods53. Even
with no new dams, the impact of farm
dams is expected to increase significantly
as inflows decline due to climate change,
as they will capture a higher proportion
of the available water. Salt interception
schemes and improved irrigation
efficiency are two recent initiatives that will
affect flows in rural areas.
Widespread reforestation, through
plantation forestry or smaller-scale
agroforestry activities, can change the
hydrology of catchments by intercepting
groundwater recharge and directly
drawing down groundwater though their
root systems (see Land and Biodiversity,
Indicator LB15). Young, rapidly-growing
trees use much more water than mature
forest, leaving less to flow into rivers,
lakes and dams. Fire may also affect
water availability through its effects on
vegetation. When regenerating forest
reaches a phase of rapid growth, typically
20–25 years after a wildfire, it uses more
water than a mature forest. Impacts
continue for another 80–100 years after
that time54 (see also Part 4.2: Land and
Biodiversity, LB8 Fire in the Victorian
Environment). It is estimated that regrowth
of vegetation following the 2003 alpine
fires will reduce flows to the River Murray
by up to 700 GL a year or 10% of mean
annual flow55.
Urbanisation, while affecting a relatively
small area of Victoria, represents an
intense disturbance to ecosystem function
(see Box IW1.2). Urbanisation affects
streamflow by making it much more
variable, reducing low flow rates and, after
heavy rain, increasing peak flow rates
and shortening their duration56. Another
significant impact on flow patterns is that
peak flow from small, frequent rain events
is dramatically increased, with changes
of up to a factor of 20 being observed
between undeveloped and developed
catchments57.
Climate change
As the climate changes, Victoria will
become warmer, water availability will
reduce and extreme events are likely to
increase in frequency. The implications
of these pressures on flow regimes are
discussed in Impacts of Climate Change
on Inland Waters.
Implications
Modification of natural flow regimes
in Victoria’s inland waters has led to
significant negative impacts on physical
habitat, ecological health, biodiversity, and
provision of ecosystem services.
The Snowy River and River Murray
exemplify the impacts already caused
by altered flow regimes on river systems.
The Snowy has suffered a build-up of
sediment, weed infestation and reduced
habitat for native flora and fauna58 (e.g.
the demise of Australian Bass population),
particularly in NSW. Similarly, the Murray
is now a heavily regulated system with an
inverted flow regime and greatly reduced
variability in flow. An assessment by
the Victorian Environment Assessment
Council of River Red Gum (Eucalyptus
camuldulensis) forests concluded that the
greatest environmental problem was the
“imminent loss or degradation of large
areas of wetlands and riverine forests
as a result of greatly reduced frequency
of flooding”59. The health of floodplain
vegetation in the Hattah Lakes, declared
an ‘Icon site’ by the Murray-Darling Basin
Commission and a Ramsar-listed wetland,
is of serious concern, with just 5% in good
condition and 76% in poor or degraded
condition60. Emergency pumping of water
to Chalka Creek and nine of the 18 lakes
in the Hattah complex as part of the Living
Murray program in 2005-06, resulted in
the improvement in tree condition at these
lakes, and a vigorous response from fish
and macrophyte communities61. In the
Barmah-Millewa Forest 75% of the River
Red Gums are in decline, although only
5% are currently in poor condition62. This
study warned that, without adequate
flooding in the near future, many tens
of thousands of hectares of forests and
wetlands may be lost, requiring centuries
to recover.
When changes in groundwater levels
lead to waterlogging and salinisation, the
impact may be severe (see Part 4.2: Land
and Biodiversity, LB6 Salinity). Wetlands
and surrounding native vegetation are
particularly at risk from rising groundwater
and salinity because of their low position
in the landscape. Between 13% and 22%
of all natural wetlands in Victoria occur
in landscapes predicted to develop
shallow watertables by 205065. Wetlands
in the Goulburn Broken and Corangamite
catchments are most at risk. Despite this,
groundwater is often overlooked and its
management has historically been underresourced.
The legacy of historic groundwater
extraction on river flow is an emerging
issue. The time lag between the
commencement of groundwater extraction
and its full impacts being observed in
rivers may be decades66. Australia still
has no agreed method for assessing the
sustainable yield of groundwater67.
Flow variability and volume underpin many
ecosystem processes in inland waters,
regulating the transport of nutrients,
sediment and salt within inland waters and
onto associated floodplains68. Changes to
flow variability and volume, combined with
altered land-use practices, have resulted
in many inland waters with modified
loads and concentrations of natural
contaminants such as nutrients69.
Assessing the future implications
of modified flows regimes requires
consideration of the cumulative impact
of the pressures presented above. Thus
future extraction and flow regulation need
to be considered in the light of reduced
water availability, higher temperatures and
evaporation resulting from climate change;
increased interception of catchment
runoff by farm dams and plantations,
reforestation and bushfire re-growth;
altered catchment processes due to
urbanisation; as well as the impact of
historic groundwater extraction. Potential
implications of these pressures on the
individual components of flow regimes are
summarised below.
Changes to cease-to-flow events
When the frequency or duration of
cease-to-flow events increase, there is
little capacity for aquatic plant and animal
species to recolonise. The increased
stress from extended periods without
flow reduces population viability70,
which is weakened further by the loss of
connectivity due to dams and weirs that
block the migration of aquatic species.
However, reservoirs and weir pools
provide some level of refuge habitat but
only for some species, notably those
which have been introduced.
Changes to low and high flows
River regulation can significantly reduce
the volume of low flows below natural
levels, and can also increase the duration
of low flows, with significant impacts on
biodiversity and ecological processes.
River regulation has been identified as
a primary cause of algal blooms, as
the creation of weir pools and low but
continuous flows of water effectively
convert them to a series of shallow,
thermally stratified lakes in summer71.
Low flows may also create barriers to
movement, and reduce in-stream habitat.
Very low summer flows can also raise
temperatures and cause a build-up of
nutrients or saline water in stagnant pools.
Over time, deoxygenation may occur,
resulting in fish deaths72.
High flows, bankfull flows and overbank
flows, including major floods, have
vital roles in maintaining floodplain and
wetland ecosystems and allowing fish
migration, sediment transport and channel
maintenance73. When these flows are
reduced, dependent ecosystems become
fragmented and degraded, and loss of
biodiversity can occur.
At present, no environmental entitlement
on any of Victoria’s northern rivers is
sufficient to create a flood, so supplying
water to floodplain wetlands often
depends on pumping. While pumping has
some advantages–for example, excluding
carp (Cyprinus carpio) and gambusia
(Gambusia holbrooki) from Hattah Lakes
during recent watering74–it subverts natural
processes such as migration and transfer
of sediment and increases the risk of lethal
‘blackwater’ events, where high levels of
dissolved organic carbon and low levels of
dissolved oxygen are present.
Absence of adequate spring floods in
recent decades has resulted in an almostcomplete
cessation of breeding by various
species, including the Great Egret (Ardea
alba), Little Egret (Egretta garzetta) and
Intermediate Egret (Ardea intermedia)75.
In the spring of 2005, environmental water
was delivered to Gunbower Forest, a
Ramsar-listed wetland, to maintain several
permanent and semi-permanent wetlands,
protect and enhance the River Red Gum
communities and provide breeding
opportunities for colonial waterbirds.
The flooding triggered breeding among
waterbirds76 and increased spawning by
several native fish species77.
Changes to seasonality
In temperate Australia, plants and animals
in floodplain and riverine ecosystems
are generally adapted to floods in winter/
spring and low flows in summer/autumn.
Changes to these patterns through flow
regulation are thought to have caused
significant changes in some Victorian
ecological communities78. Large dams
have the potential to capture seasonal
floodwaters, which are then stored and
released for irrigation during the dry
season. This reverses or inverts the
seasonality of flow and diminishes the
reproductive success of many aquatic
species. For example, changing the
seasonality of flow may remove the
necessary habitat requirements for the
spawning and survival of fish such as the
Golden perch79.
Changes to variability
The variability of flow in a river can strongly
influence aquatic habitat availability
and plant and animal assemblages80.
A reduction in the daily variability of
summer low flows in rivers can reduce
opportunities for fish to move between
habitats. Exotic species of plants and
animals may also benefit from flows with
less daily and monthly variation. For
example, introduced Carp and Gambusia
species are found in greatly increased
numbers in regulated reaches where flow
varies little, usually to the detriment of
native fish species81.
Management responses
Given the importance of water regimes
to ecosystem function, management
responses should protect natural water
regimes and retain or reinstate as many
of the features of the natural water regime
as possible. Connections between inland
water systems need to be recognised
through an integrated approach to the
management of wetlands, rivers and
groundwater systems. Flow regimes are
managed through the water allocation
framework, and strategies and plans at
a range of scales, from regional down
to sub-catchment (see Part 3.2: Water
Resources).
Response Name
Creating the Environmental Water
Reserve (Our Water Our Future, Actions
2.2, 3.4 and 3.5)82
Responsible Authority
Department of Sustainability and
Environment
Response Type
Legislation
The environment’s right to water, known
as the environmental water reserve
(EWR), was only given formal recognition
in the water allocation framework in
200583. In most rivers and aquifers, the
EWR is provided by capping the volume
of water available for consumption. In
rivers where flow is regulated by dams,
water is provided as ‘passing flows’
for environments downstream84. In
unregulated rivers, the EWR is delivered
through streamflow management plans
that manage the diversion of water85.
Entitlements of water are also held by
catchment management authorities
for environmental purposes. These
entitlements often comprise only a fraction
of the overall EWR. In the northern region,
for example, only about 4% of the EWR is
held as a legal entitlement86.
The mapping of groundwater dependent
ecosystems such as streams and
terrestrial vegetation, will be completed
by The Department of Sustainability and
Environment in 2009. The environmental
water requirements of these ecosystems
must be specified differently to those
of surface water ecosystems. The
groundwater level regime is critical, and
must be managed according to locationspecific
factors. The methodology for
delivering these water requirements will
be trialled in the Glenelg-Hopkins CMA
region.
Recommendations
IW1.2 Government should provide
environmental water requirements for
groundwater-dependent ecosystems
once the delivery methodology has
been finalised.
IW1.3 Review allocations between
all sectors within the current 15-year
period, taking into account real and
projected water availability.
IW1.4 The cyclical review of water
allocations should be conducted on
an ongoing basis over a shorter period
than 15 years, and the findings made public.
Response Name
Indicator IW4 Delivering the
Environmental Water Reserve
Responsible Authority
Department of Sustainability and
Environment
Response Type
Policy/strategy
The different components of the surface
water EWR are delivered through the
allocation framework. Catchment
Management Authorities are responsible
for the delivery of Environmental
Entitlements in accordance with Annual
Watering Plans. Water Authorities are
responsible for complying with passing
flow conditions on Bulk entitlements.
Across Victoria, there are some 450 Bulk
Entitlements and 600 points at which
passing flow conditions are stipulated.
Streamflow management plans have been
completed for the Hoddles and Diamond
Creeks, the Plenty River, Olinda Creek,
Stringybark Creek and the Pauls, Steels
and Dixons Creeks.87 Management plans
have been developed for nine high-priority
groundwater management areas. These
plans do not deliver the groundwater
environmental water reserve, which is
still in development, but nevertheless
manage the extraction of groundwater.
A further 15 plans are in progress for
high-priority water supply protection areas.
Management plans will eventually be
written for all 24 groundwater management
and 40 groundwater supply protection
areas in Victoria88.
In many rivers and aquifers the current
EWR is inadequate and vulnerable,
placing environmental values at risk89.
In 2006–07, about 40 temporary
qualifications to environmental flows
were made in Victoria90, as part of the
Government’s drought contingency
response. To date no water has been
delivered to the rivers of the Central
region as a result of the Central Region
Sustainable Water Strategy. Additional flow
committed to the Yarra River has been
delayed by the Minister for Water until
storage levels recover91. Such delays pose
a serious risk to the environment.
The delivery of environmental entitlements
in the Northern Region is now dependent
on a return to ‘normal’ rainfall. In the
Loddon, Murray, Campaspe and Goulburn
Rivers, where the EWR has been recently
boosted with low reliability water shares,
low streamflows have meant this water
is not yet available. This policy appears
inconsistent with current projections
for climate change, and appears to
undermine a major benefit of creating the
EWR, which was to give the environment
an entitlement with legal status equivalent
to that for water allocated to consumption.
During times of low streamflow, the water
allocation system reduces environmental
flows more than it reduces water for
consumptive uses. Some components
of the EWR, such as water above the
cap, and spills from storages, are also
vulnerable to climate change92 (see
Impacts of climate change on Inland
Waters, Implications).
If current low streamflows persist, the State
Government should be prepared to review
allocations between all sectors within the
current 15-year period, taking into account
real and projected water availability and
the financial implications.
Coordination of State and Commonwealth
Governments has proved a barrier to
improving the condition of the Snowy River
and River Murray. An Inter Governmental
Agreement (IGA), on the management
of the River Murray was signed by the
Commonwealth and State Governments
on 3 July 2008. Water recovery for the
Snowy River is being managed by a joint
(Commonwealth, Victoria and NSW)
Government Enterprise with 142 GL of
water recovery targeted for 2009, but now
delayed to 2012. Planned releases for
2006-07 amounted to only 46 GL93.
The use and carry over of environmental
entitlements are annually reported in
the Victorian Water Accounts. Water
Authorities and Catchment Management
Authorities report on compliance with
conditions of bulk entitlements for which
they are responsible94. The standard
of compliance reporting is currently
being increased through better auditing
processes and new instrumentation at a
number of these points95.
Recommendation
IW1.5 The Government should disclose
the reasons for, and likely impact of, the
qualification of environmental flows.
Response Name
Improving the Environmental Water
Reserve
Responsible Authority
Department of Sustainability and
Environment
Response Type
Policy/strategy
The Victorian Government has made
significant commitments to improve
the EWR in 100 high-priority reaches
of rivers with dams and weirs96. These
commitments have been outlined in
Our Water Our Future and the Central
Region Sustainable Water Strategy. The
Regional Sustainable Water Strategies
enable investment in programs to
increase flows to levels consistent with
ecological objectives and provide adaptive
responses to the uncertainties associated
with climate change. For example, further
improvements to bulk entitlements are
made through this process. A condition of
these programs is that that there should
be no impact on existing entitlements. This
approach protects the rights of entitlement
holders but limits the options available for
improving flow regimes.
The Government’s policy position in
relation to water recovery as outlined in
Our Water Our Future is to:
• Invest in distribution savings
• Invest in water re-use and recycling
• Change system management
• Enable water donations
• Invest in reconfiguring irrigation systems
and other local adjustment projects
providing long term environmental and
social or industry benefits; and
• Purchase water through the water
Market
Currently, initiatives are focused on
investing in improving the efficiency of
distribution networks, enabling donations
and investment in reconfiguring irrigation
systems. The volumes of water that will be
recovered, and the certainty of allocations
of this water to the environment, are to
be determined. In unregulated rivers,
stream flow management plans are to
be developed on a priority basis, with
government co-investing to increase
environmental flows to meet agreed
ecological objectives.
Some environmental entitlements were
also increased as part of the revised
allocation framework, in particular 120,000
ML for the River Murray and 96,000
ML for the Goulburn River (see Figure
IW.5). However, these shares are ‘low
reliability shares’ which may not always
be available. Under climate change,
their availability is likely to decrease.
For example, low reliability water shares
in the Goulburn River are expected to
be available only seven years in 100 by
205597. Although improvements to the
EWR have been made on paper (as
per Figure IW1.5), water scarcity and
qualifications to environmental flows have
constrained delivery of this water in recent
years.
Recycled water is increasingly being
considered as a means by which
environmental flows can be increased to
meet ecological objectives and reduce
demand on surface water supplies (See
Part 3.2: Water Resources).
Recommendations
IW1.6 Government should act with
urgency to increase environmental
water reserves where they are
currently insufficient to keep rivers in a
sustainable condition, including buying
back water. In particular, floodplains
need floods to continue functioning as
floodplain ecosystems.
IW1.7 Review water trading rules to
remove impediments to buying water to
add to the environmental water reserve.
IW1.8 Adopt a new term for
environmental flows that does not
have connotations of being ‘just for
the environment’, and expresses the
importance of maintaining water quality
and river health. For example, “essential
baseflow” could be used to describe
minimum flows required during low-flow
periods to maintain water quality and
river health.
Response Name
Restoring the Balance in the Murray
Darling Basin Program
Responsible Authority
Department of Environment, Heritage,
Water and the Arts
Response Type
Water Entitlement Buy-back
The Restoring the Balance Program is a
$3.1 billion program to buy back, over 10
years, entitlements from willing sellers in
the over-allocated Murray Darling Basin.
It a priority action of the Commonwealth
Government’s $12.9 billion Water for
the Future initiative, which also includes
actions for climate change, water
conservation and efficiency measures
including nearly $6 billion to refurbish
irrigation schemes, and securing urban
water supplies.
Restoring the Balance recognises the
need for immediate action to address
over-allocation, and aims to acquire water
from willing sellers, and use the water
allocated to them to improve the health of
rivers, wetlands and floodplains.
An initial $50 million water buy-back in
2007-08 aimed to secure entitlements
to 35,000 ML of water. A new round
of purchases worth $400 million was
announced in September 2008, focusing
on the northern Murray-Darling Basin in
New South Wales and Queensland.
In Victoria, the volume of water which can
be permanently traded out of a particular
irrigation area in any one season is limited
to 4%99. This trading rule limits the social
impacts of water leaving an area, but may
also limit opportunities to quickly purchase
water for the environment.
It is important that water is bought
strategically, and before re-furbishing
infrastructure, to ensure the outcomes
of these programs do not conflict. The
broader and longer term social and
economic implications of these decisions
may be regionally significant, and
measures to identify and address them must be considered.
Response Name
Victorian Environmental Flows
Monitoring and Assessment Program
Responsible Authority
Department of Sustainability and
Environment
Response type
Monitoring program
The Victorian Environmental Flows
Monitoring and Assessment Program
(VEFMAP) was established to coordinate
the monitoring of ecosystem responses
to environmental flows in eight stressed
rivers100. These rivers, where delivery
of environmental flows is expected or
underway, are the Broken, Goulburn,
Loddon, Campaspe, Wimmera, Thomson,
McAlister and Glenelg101. VEFMAP is
in three stages, the first two of which
are complete: The development of an
overarching Victorian framework for
monitoring ecosystem responses to
environmental flow releases; and the
development of targeted monitoring
and assessment plans for individual
river systems. The third stage, which is
underway, includes implementation of
monitoring, data collection and analysis,
interpretation and program review after
three years.
Due to current water shortages, releasing
water for environmental purposes has
become increasingly difficult, yet water
managers are expected to show shortterm
benefits from environmental flows in
rivers that have been subject to decades
of degradation. Programs such as
VEFMAP are required to demonstrate the
benefits of environmental water in order
to counter purely cost based arguments
for qualifying or diminishing environmental
flows. Water managers should continue
to build knowledge and expertise at
prioritising water-dependent environmental
assets, and protecting those of highest
value.
Evaluation of responses to flow
Regimes
Streamflow in Australia is highly variable.
In response, human settlements have
transformed inland waters into a complex
and extensive system for harvesting,
transporting and controlling the movement
of water102, with the highest levels of percapita
storage in the world103.
Recognition of the reality of irretrievable
ecological damage caused by past
and current management practices, a
burgeoning population, prolonged drought
and the threat of climate change have
increased the urgency for Government
action.
Significant improvements in the way
water is managed for the environment
have occurred in the past decade.
These include the adoption of a revised
allocation framework which recognises the
environment’s right to water and caps the
maximum of water that can be harvested
from each basin; the designation of
catchment management authorities as
managers of the environmental water
reserve; funding commitments to recover
water for the environment; the adoption
of the FLOWS methodology for assessing
environmental flows; and improved water
accounting through the Victorian Water
Accounts.
The current level of development of
water resources, and ongoing drought,
greatly constrain actions both to further
modify and to improve the condition of
flow regimes. New instream storages are
not supported under current government
policy and further direct physical changes
to rivers such as channelisation and the
construction of levees, are now limited
in extent, aside from rehabilitation works
(see Part 3.2: Water Resources, Major
storages). Existing infrastructure can
be upgraded, for example to reduce
unaccounted water, but is largely fixed and
needs to be managed to achieve the best
outcomes for the entire system.
In all basins water needs to be shared
between competing consumptive and
non-consumptive uses, within the context
of catchment impacts on hydrology,
drought and climate change. Management
is coordinated at a range of scales,
from regional down to sub-catchment,
through inter-related strategies and
plans. Important programs to overcome
knowledge gaps, such as the assessment
of groundwater dependent ecosystems,
are relatively recent and are yet to be fully
incorporated into management planning.
The actual sharing of water between
competing users, however, occurs
through the allocation framework, which
is therefore central to efforts to improve
flow regimes, particularly in over-allocated
basins.
The principle of protecting private rights to
water is central to the Victorian allocation
system104. Entitlements to the use of
water, which were ongoing in tenure,
were granted as water resources were
developed. The allocation framework was
revised in 2004 through the Our Water Our
Future White Paper, but entitlements were
not reviewed in terms of environmental
requirements or projected resource
availability. The only mechanism by which
entitlements can be directly adjusted is
the Statewide Water Resource Review,
which occurs on a 15 year cycle. The
first Statewide Water Resource Review
is to be completed in 2019, but this is
too late in the context of the condition of
inland waters, water scarcity and climate
change105.
The development and implementation of
Regional Sustainable Water Strategies will
help to improve flow regimes and provide
adaptive responses to the uncertainties
associated with climate change, in order
to minimise any adjustments required
under the Statewide Water Resource
Review.
Given the centrality of the allocation
framework to water resource
management, it is vital that this system
does not hinder the establishment of
adequate flow regimes, nor further
disadvantage environmental flows under a
drying climate. A greater range of options
for improving flow regimes needs to be
considered, including adjustments to the
allocation framework and entitlement buybacks
from willing sellers, to sufficiently
meet the seasonal flow requirements of
many rivers in Victoria.
Allocation decisions are made in the
context of meeting customer requirements
but also in the context of the degradation
of inland waters and likely climate change.
Caps on surface and ground water
extraction across Victoria were established
under the Our Water Our Future White
Paper, in addition to those already in place
in the Murray-Darling Basin. Caps prevent
further water resource development in
over-allocated or fully allocated systems,
but do not address current levels of overallocation,
or the impacts of altered flow
regimes.
Investment in water infrastructure
and water recovery by the Victorian
government, as well as other states
and the Commonwealth, needs to be
coordinated to the highest level, to avoid
projects with conflicting outcomes.
Both Victorian and Commonwealth
Governments are making substantial
investments to refurbish irrigation
infrastructure. The Commonwealth
Government, however, has also prioritised
entitlement buy-backs; whereas the
Victorian Government has placed less
priority on entitlement buy-backs, and has
used rural water to improve the security
of supply for the urban centres of Ballarat
and Bendigo, and soon Melbourne.
The Index of Stream Condition
assessments and independent reports
on the health of the River Murray River
clearly indicate that these improvements
are absolutely necessary, and in some
cases must go further. Even the highest
volume of water recommended for return
to the Murray (1,500 GL) is only given a
moderate chance of restoring the river to a
healthy condition106.
In many rivers and aquifers the current
EWR is inadequate and vulnerable,
placing environmental values at risk107.
In 2006–07, about 40 temporary
qualifications to environmental
flows were made in Victoria108, and
environmental flows were also qualified
in 2007-08 as part of the Government’s
drought contingency response. From
the perspective of the environment,
withholding flow at these times poses a
serious risk, and should not be used on an
ongoing basis.
Where over-allocation has occurred, water
must be recovered to augment the flow
regime. The current State Government
policy is to protect existing entitlements
from any impacts, including adjustment to
entitlements and entitlement buy-backs.
Other approaches such as improving
the efficiency of water supply systems
and reducing demand are used to
augment environmental entitlements (see
Management Responses). While this
approach protects the rights of entitlement
holders, it also limits the options available
for improving flow regimes, and to date
has not sufficiently met the seasonal flow
requirements of many rivers in Victoria.
Recommendation
IW1.9 Improve the awareness and
understanding within the community of
the importance of environmental flows
for inland waters, and provide regular,
consolidated reports on progress
against the actions and outcomes within
Our Water Our Future and the regional
sustainable water strategies
For further information
Monthly Water report, Victorian Water
Accounts
http://www.ourwater.vic.gov.au/monitoring
IW2 In-stream and Wetland Habitat
Key findings
• River channels and instream habitat,
including wetlands, were historically
modified without an understanding of
the consequences. Many large-scale
changes such as erosion and draining
of wetlands are irreversible, and the
historic legacy of channel modification
still places pressure on in-stream
habitat.
• In 2004, just 6% of the major rivers
and tributaries assessed by the Index
of Stream Condition had in-stream
habitat in good condition, based on the
presence of large woody habitat, bank
stability and barriers to fish passage.
• By 1994, 37% of naturally occurring
wetland area had been lost, mainly
due to drainage. An inventory showing
the extent of wetlands has not been
updated since then.
• The statewide condition of remnant
naturally occurring wetlands are not
available in detail. An Index of Wetland
Condition assessment technique has
been developed and is currently being
finalised.
• River channels and wetland habitats
are now managed with much greater
sensitivity to, and understanding of, the
ecological significance of their various
components and processes. Remnant
naturally occurring wetlands, particularly
those on private land, remain vulnerable
to incremental loss and degradation in
quality.
• In many cases, restoration works involve
putting back what was taken away many
years ago. The ongoing investment
and effort required show the benefits of
avoiding damage in the first place.
Description
In-stream habitat describes the physical
form of a waterway and the features of
the habitat. Changes to in-stream habitat
can significantly influence the distribution,
population abundance and community
structure of aquatic biodiversity109.
River channels and in-stream habitat
were historically modified without an
understanding of the consequences, and
the historic legacy of channel modification
still places pressure on the in-stream
habitat of rivers and wetlands. Clearing
of catchment and riparian vegetation and
changes in land use have led to bed and
bank erosion, severely modifying channel
structure. Deposition of sediments on river
channels and floodplains has covered
and removed major habitat features such
as riffles and pools in streams. Activities
that physically disturbed the substrate,
such as gold mining, dredging and bridge
building, also contributed to this problem.
There is increasing evidence that many
rivers in Victoria previously contained
woody material, such as large branches
and whole trunks, along their banks and
within their channels. In the past, this
material was removed from many rivers to
allow boat passage and increase channel
capacity. The removal of trees from
riparian areas has significantly reduced
the amount of large woody habitat
available for aquatic biota, particularly in
lowland areas where clearing has been
more extensive. The critical importance
this habitat plays in the physical and
ecological health of rivers was only
realised later.
Large woody habitat influences the
shape, depth and flow of water in inland
waters. It provides a surface upon which
microscopic plants can grow, and habitat
for in-stream invertebrates such as snails
and insect larvae. Large woody habitat
also provides shelter from predators and
forms an essential spawning habitat for
several native fish species, including the
river blackfish (Gadopsis marmoratus)110.
Even though the removal of woody
habitat in rivers and streams is listed as
a potentially threatening process under
the Flora and Fauna Guarantee Act 1988,
until recently the removal of snags was
widespread in many rivers. The challenge
today is to demonstrate the positive
benefits of maintaining woody habitat and
recognise the need for restoration works.
Restoration itself may be difficult in many
instances as the source of woody habitat
(i.e. riparian vegetation) is often degraded.
The introduction of barriers has severed
the connectivity of inland waters,
preventing the longitudinal and lateral
movement of fish and other biota, and
interrupting the transport of organic
materials and sediment. Barriers include
dams, weirs, causeways, culverts, levee
banks, erosion control structures and
regulators. The lateral movement of water
onto the floodplain is essential, but these
links have been lost throughout the State.
The presence of fish barriers in Victorian
rivers and streams is also listed as a
potentially threatening process under the
Flora and Fauna Guarantee Act 1988.
Objectives
• Protect and restore in-stream habitat
through activities such as re-snagging,
bank and bed stabilisation, revegetation
and the reconstruction of habitat
diversity
• Maintain and, where possible, restore
longitudinal (upstream-downstream),
lateral (stream-floodplain), and vertical
(surface-groundwater) connectivity
• Manage the catchment to protect
against and reduce degradation of instream
habitat
State
Indicator IW5 Condition of in-stream
habitat in major rivers and tributaries
Important aspects of in-stream habitat
are substrate type and diversity, channel
shape, presence of woody habitat, and
connectivity. Assessment of in-stream
habitat (the Physical Form Index of the
ISC) measures three factors: the impact
of artificial barriers to fish passage, the
presence of large woody habitat and the
level of bank stability. The presence of
riparian vegetation is discussed separately
in IW3 Riparian Vegetation.
In 2004, just 6% of in-stream habitat
assessed was found to be in good
condition with the majority of reach length
assessed as being in moderate (69%) or
poor condition (25%).
The Snowy and East Gippsland basins
have the highest proportion of reach
length with in-stream habitat in good
condition (see Figure IW2.1). In contrast,
12 basins had no assessed reaches with
in-stream habitat in good condition, and
a further 11 basins had less than 10%
of reach length in good condition. The
basins with the greatest proportion of
reach length in poor condition were the
Hopkins, Thomson, Loddon and Avoca
basins, with 49% or more of reach length
in poor condition (see Figure IW2.1). While
the northern two-thirds of the Thomson
basin are forested, the lowland reaches
have been all been desnagged in the past,
and the surrounding land is heavily used
for agriculture111. As a result, in-stream
habitat was assessed as being in a
poorer condition in this basin than may be
otherwise expected.
Barriers to fish passage
Across Victoria, 49% of river reaches
assessed were affected by at least one
artificial barrier that completely blocks fish
migration. Fish passage to almost 25%
of reaches was only intermittent, while
only 27% of reaches were not affected
by barriers, indicating that this remains a
serious issue for many Victorian streams.
Artificial barriers, such as dams and
weirs, have had a serious impact on the
distribution and abundance of many
native fish species (see Part 3.2: Water
Resources)112.
Presence of large woody habitat
Large woody habitat was in poor condition
in 52% of the reaches assessed, with
only 20% of total reach length in good
condition and 28% in moderate condition.
In basins where large woody habitat
was mostly in good condition—for
example, the Mallee, East Gippsland and
Mitchell—this reflected the presence of
areas of largely unmodified rivers where
little riparian vegetation was removed in
the past. Basins in mostly poor condition,
such as the Millicent Coast, Barwon and
Kiewa basins, contained large tracts of
heavily modified waterways with poor
riparian tree cover and a history of
clearing.
Bank stability
Bank stability in over 40% of the reaches
assessed was in good condition with
49% being in moderate condition and
the remainder in poor condition. Channel
instability and bank erosion still pose a
threat to in-stream habitat condition.
The Snowy, Bunyip and Millicent Coast
basins had over 80% of all reach
length assessed with bank stability in
good condition. This result reflects the
remoteness and the rocky nature of bed
and banks, which helps to stabilise the
in-stream habitat of some rivers. Riparian
vegetation also stabilises riverbanks, and
those reaches where minimal clearing has
occurred will generally be the most stable.
Many examples of rivers and streams
in Victoria have undergone catastrophic
erosion. Within Melbourne, there are
examples of streams (e.g. Gardiners
Creek and Koonung Creek) where
modifications have increased the stream’s
dimensions up to 100-fold113 (see Box
IW2.1). The lower sections of the Latrobe
River, downstream from Yallourn Weir,
have been extensively de-snagged and
cleared and shortened from 165 km to 139
km by straightening the river channel114.
A major motivation for this work was
to limit flooding but extensive erosion
of the river channel has resulted. The
Ovens River valley has had bank stability
reduced by alluvial gold mining and gravel
extraction115.
Indicator IW6 Extent of wetlands
compared to pre-European settlement
An inventory completed in 1994, which
presents the most recent data available,
showed that 37% of naturally occurring
wetland area has been lost (see Table
IW2.1 and Figure IW2.3)116. The extent of
wetlands includes coastal marshes, for
example much of Western Port, Corner
Inlet and Gippsland Lakes.
Deep freshwater marshes (70% lost by
area), shallow freshwater marshes (60%
lost by area) and natural freshwater
meadows (43% lost by area) have
declined by the greatest extent. This is
because their temporary and shallow
nature makes these wetlands relatively
easy to drain. Temporary ponds, for
example, have been converted to
agricultural land by ploughing and
subsequent cropping.
Some of the areas most affected by
wetland drainage in Victoria are the South
West and the irrigation areas around
Kerang and Shepparton117. Closer to
Melbourne, drainage of the Koo-Wee-Rup
swamp, which originally covered 40,000
ha, has caused ongoing damage to the
ecology of the rivers and streams of the
Bunyip basin, and also to Western Port
(see Figure IW2.5).
Alpine mossbeds, a type of shallow
freshwater wetland, were not mapped and
classified in the 1994 wetlands inventory.
These wetland environments are unique
to Victoria’s alpine and sub-alpine areas.
Subsequent mapping has estimated that
alpine mossbeds have reduced in area
by up to 50% since European settlement.
Various types of disturbance such as
weed invasion, especially by willows,
and trampling and grazing by livestock,
threaten the condition of mossbeds. Once
disturbed, recovery of alpine mossbeds
is very slow. With their elevated and
restricted distribution, alpine mossbeds
are at risk of further contraction from
climate change.
In addition to natural wetlands, there
are some 3,900 constructed wetlands
which cover approximately 108,100
ha118. Some constructed wetlands have
high environmental significance, such
as the lagoons of the Western treatment
plant at Werribee, which form part of
the Port Phillip Bay (Western Shoreline)
and Bellarine Peninsular Ramsar site119.
The multiple benefits that wetlands offer,
such as filtration and nutrient cycling are
being designed into drainage and effluent
treatment systems. Melbourne Water
Corporation has a constructed wetland
program which aims to achieve a 100 t per
year reduction in total nitrogen loads in
Melbourne’s urban stormwater by 2010120.
Opportunities for the construction of these
wetlands are increasingly constrained by
the availability and costs of good sites.
Recommendation
IW2.1 Improve protection for wetlands
on private land
Pressures
Pressures on in-stream and wetland
habitat reported elsewhere in this Report
include uncontrolled stock access to
riparian zones (IW3 Riparian vegetation,
Pressures); River regulation (IW1 Flow
regimes, Implications); water quality (IW4
Water quality, Implications) and Climate
Change (IW6 Impact of climate change on
Inland Waters, Implications).
Channelisation
Channelisation was historically used to
reduce the duration and frequency of
flooding in floodplain areas, and involved
one or more of the following:
• De-snagging, or removing the wood
naturally present in streams (see below)
• Straightening, by cutting through river
bends to steepen the channel. The
most extreme example is the Latrobe
River in Gippsland, where the swampy
floodplain was saturated for up to half of
the year until drains were installed
• Artificial levees. Many lowland streams
in Victoria have artificial levees to
reduce the frequency of flooding on the
floodplain (see Figure IW2.6)
As well as directly modifying in-stream
habitat, these works often caused
extensive erosion (for more information
on erosion see below). The locations of
historical channelisation works, as well
as works to reduce erosion, are shown in
Figure IW2.7. Urbanisation has resulted
in extensive modifications to in-stream
habitat (see Box IW2.1).
Concerted efforts to improve the
management of river channels and
floodplain management, and restore
damage from past practices, have started
to control these pressures on habitat.
However, the legacy of these practices is
still evident in many streams.
Wetland drainage
Wetlands have been drained to reduce
waterlogging in agricultural land. Much
of the alluvial area of the State (the valley
floors) was originally wetland. These areas
were reclaimed by digging drains, which
often eroded into gullies122. Temporary
ponds, which are important habitats,
have been lost through ploughing and
subsequent cropping.
Removal of woody habitat
Removal of woody habitat from in-stream
areas, often referred to as de-snagging,
was once considered an essential
component of good river management
(see Figure IW2.7). De-snagging was
believed to improve streamflow, reduce
the severity and extent of flooding,
improve navigation, make recreation
safer and assist with substrate removal
(sand, gravel and gold extraction)124. As
recently as 2003, it was reported that
removal of snags, or realigning them to
reduce perceived problems with erosion or
changes in stream alignment, continued in
many rivers and streams across Victoria125.
There is now a general policy that wood
should not be removed from rivers.
Removal of trees, shrubs and groundcover
from riparian areas has significantly
reduced the amount of large woody
habitat available for aquatic biota,
particularly in lowland areas where
clearing is more likely to have occurred.
Recommendation
IW2.2 Increase protection of floodplain
habitat, including wetlands, wood on the
floodplain and in floodplain channels.
Erosion and sedimentation
Erosion is a natural process that
contributes to turbidity, phosphorus and
nitrogen concentrations in surface waters.
Within catchments mostly undisturbed by
human activity, the level of sediment input
is relatively low but can naturally vary with
geology, soil type, rainfall and landform.
Flushes of high sediment loads can
occur naturally from the consequences
of extreme weather and climate variability
(e.g. bushfire, floods, landslips and
vegetation loss during drought). See Part
4.2: Land and Biodiversity, Erosion for
more information.
Sediment inputs into aquatic systems
have increased considerably since
European settlement of Victoria126, largely
as a result of land clearing and removal
of riparian vegetation. This has been
particularly detrimental as plants bind
the soil and retain coarse sediments.
The increased intensity of flow events in
urban catchments has also dramatically
increased rates of erosion (see IW1 Flow
regimes, Pressures; Box IW1.2).
The significance of gully and riverbank
erosion on sediment loads is supported by
computer modelling of sediment transport
in the Goulburn catchment. Gully erosion
and riverbank erosion were identified
as the major sources of sediment in
the catchment, contributing in excess
of 90% of the total sediment load127. By
comparison, sheet-wash erosion was less
than 10% of the total catchment sediment
load.
As a result of extensive erosion, some
rivers now have large sand ‘slugs’
moving slowly downstream, reducing
environmental values for aquatic fauna.
For example, a large sand slug in the
Snowy River near Orbost threatens local
populations of Australian bass (Macquaria
novemaculeata).
Large scale fires in 2003-04 and 2006-07
dramatically increased vulnerability to
erosion, leading to in-stream habitat loss,
poor water quality and the deposition of
large amounts of soil and other materials
in stream beds and lakes downstream of
the burnt areas.
Barriers preventing the passage of
aquatic biota
Infrastructure for management of water
resources severs the connectivity of inland
waters both longitudinally (upstream–
downstream) and laterally (stream–
floodplain). Construction of road crossings
and weirs has significantly increased
the number of barriers to the passage of
biota. Other barriers such as levees which
reduce the lateral movement of water
have effectively isolated rivers from their
floodplains, blocking regeneration within
these ecosystems and removing habitat,
nutrient and organic matter crucial for
stream function.
In 1999, the State Fishway Program
conducted an inventory of potential
barriers to fish movement across the
State, and identified up to 2,438 potential
barriers, with farm dams and weirs making
up the largest proportion128 (see Part
3.2: Water Resources, Pressures on the
Environment). The program also identified
a significant number of streamflow
monitoring sites, which made up about
30% of the total barriers. The assessment
did not record culverts and road crossings
but these can also form an effective barrier
to fish movement129.
Recommendation
IW2.3 Remove all redundant in-stream
barriers or provide fish passage at all
artificial barriers.
Alluvial gold mining
Alluvial gold mining occurred throughout
Victoria from 1852 until the late 1980s.
Even in the 1980s, extensive lengths of
the state’s stream network were available
for eductor dredging (see Figure IW2.8).
Eductor dredges pump material from the
stream bed through a sluice box, which
captures gold and discharges the residue
back to the stream130. Combined with
gravel extraction, these practices have
mobilised vast quantities of sediment, and
greatly reduced stream bed and bank
stability131.
Implications
Removal of woody habitat reduces
available habitat for fish and other aquatic
and terrestrial organisms, and has a
significant impact on channel morphology,
creating uniform drainage channels, with
fewer channel features such as scour
holes and bars132.
Implications include local extinctions and
degradation of downstream habitat. In
lowland streams with silty or sandy stream
beds, woody habitat may form the major
stable habitat. Removing these structures
affects entire food chains. Increasing
uniformity of the river channel through
loss of woody habitat or erosion reduces
the availability of refugia from high flows
during floods, reducing the capacity of
biota to recover from these events133.
Loss of connectivity threatens biodiversity
and ecosystem resilience. A significant
impact is the direct exclusion of migratory
fish (e.g. Murray cod and golden perch)
from their spawning grounds in estuaries
or headwaters134. The lack of connectivity
in these rivers also reduces the prospect
of re-colonisation when conditions
improve.
Macro-invertebrate populations are
also affected by the lack of longitudinal
connectivity, with about 40% of expected
families missing from areas immediately
below dams in Victoria135. This is attributed
to loss of re-colonisation opportunities
upstream 136.
Other implications of loss of connectivity
include reduction in diversity and
abundance of accessible habitat, fish kills,
increased local predation by birds or other
fish and reduction in genetic diversity137.
Ecosystem services provided by
in-stream habitat are economically
important. Recreational inland fisheries
benefit from in-stream habitat in good
condition. Erosion of banks can intrude on
productive land. Public and private assets
such as roads and bridges may also be
threatened.
The economic value of unmodified
wetlands is often greater than that of
wetlands which have been converted for
other purposes138. For example, the loss
of wetlands can reduce the capacity of the
land to mitigate floodwaters or stormwater,
because wetlands act as water storage
points in the landscape and can reduce
the speed at which water moves across
the land.
Management responses
Management of in-stream habitat is
guided by the Victorian River Health
Strategy, and delivered through the
Victorian River Health Program (see
Introduction). On private land, community
organisations such as Landcare have
been instrumental in addressing issues
such as erosion (see Part 4.2: Land and
Biodiversity).
Response Name
Individual projects performed as part of
regional river health strategies
Responsible Authority
Department of Sustainability and
Environment; catchment management
authorities and Melbourne Water
Response type
On-ground works
The Victorian River Health Strategy outlines
statewide targets for the protection of
in-stream habitat (see Table IW2.2). Since
2002, catchment management authorities
and Melbourne Water have worked
towards these targets by implementing
individual projects guided by regional river
health strategies. These targets appear set
to be achieved, providing adequate levels
of funding are maintained. The extent of
degradation of in-stream habitat allows
scope for ambitious ‘stretch’ targets to be
set in the future.
Recommendation
IW2.4 More ambitious targets for
the rehabilitation of in-stream habitat
beyond 2011 should be included in the
Victorian River Health Program, given
the low proportion of reaches in good
condition.
Response Name
Draft Index of Wetland Condition
Responsible Authority
Department of Sustainability and
Environment;
Response type
Monitoring tool
The Draft Index of Wetland Condition
(IWC) has been under trial since
November 2005 (see Box IW2.2). It is
currently being finalised by DSE. Given
the lack of information on the condition of
wetlands across the State, the IWC should
be implemented as soon as possible.
Response Name
Victoria’s Native Vegetation Management
– A Framework for Action
Responsible Authority
Department of Sustainability and
Environment; and catchment
management authorities
Response type
Strategy/policy
The native vegetation framework is the
main tool for preventing further loss of
vegetation and habitat (see Part 4.2:
Land and Biodiversity). To protect wetland
habitat on privately owned land, clearing
regulations are complemented by other
measures, including education programs
delivered by catchment management
authorities.
The absence of a statewide wetland
inventory since 1994 has made it difficult
to ascertain recent changes to the
extent of wetlands and the impact of
management responses such as the
native vegetation framework. The specific
reporting of wetland vegetation should
be included as part of the ongoing
development of accounting processes for
native vegetation. Individual catchment
management authorities are in the process
of mapping the extent of wetlands. The
improved management of riparian zones is
a crucial factor in the protection of wetland
vegetation and offers great opportunities
for maintaining and improving the values
of wetlands and inland waters (see IW3
Riparian vegetation, Implications).
Recommendation
IW2.5 The reporting of wetland
vegetation should be included as part of
the ongoing development of accounting
processes for native vegetation (Net
Gain reporting).
Evaluation of responses to
in-stream and wetland habitat
The Victorian River Health Program
Report Card 2005 reports satisfactory
progress towards the targets to reinstate
in-stream habitat and protect high-value
public assets142. Assessing improvement
in the status of designated freshwaterdependent
focal species, such as native fish
populations, requires consistent statewide
monitoring, and this is currently being
implemented throughout Victoria (see IW5
Aquatic fauna).
River channels are now managed with much
greater sensitivity to, and understanding
of, the ecological significance of its various
components and processes. On ground
works are being delivered throughout the
State using current best practice. To enable
the systematic restoration of in-stream
habitat, the Victorian River Health Program
would benefit from long-term funding,
which currently fluctuates from year to year.
In many cases, restoration works involve
putting back what was taken away many
years ago. The ongoing investment and
effort required show the benefits of avoiding
damage in the first place.
Inland wetlands have been significantly
reduced in extent and, in addition to
protection from gross clearing or drainage,
they need to be protected from incremental
loss and degradation in quality. It is therefore
important that proactive management of
wetlands is acknowledged as an integral
part of habitat management.
For further information
Modification of channels; history of
stream management works: Department
of Water Resources (1989) An
Environmental Handbook
Wetlands information:
http://www.dse.vic.gov.au
DSE/nrence.nsf/childdocs/8946409900BAC6344A256B260015D4AFBC30FFF2D27FA86DCA25729E000419C
D?open
IW3 Riparian Vegetation
Key findings
• Riparian vegetation in good condition
supports the resilience of both
aquatic and terrestrial ecosystems,
allows recovery from disturbance and
maintains biodiversity.
• Riparian land is valued for many human
uses such as agriculture and recreation,
but as a result riparian vegetation has
been degraded.
• Uncontrolled stock access to riparian
zones continues to be the major
pressure on riparian vegetation statewide.
• In 2004, 14% of reach length assessed
across Victoria was found to have
riparian vegetation in good condition.
Nearly half the reaches assessed
had poor connectivity of vegetation.
Groundcover weeds were widespread in
riparian zones, but while shrub and tree
weeds were less common, their impact
on ecology was greater.
• About 30,000 km of Crown water
frontages along rivers in Victoria, and
a sizeable proportion are licensed to
abutting owners, mainly for grazing. To
date, the conservation intent of policy
for these frontages has not translated to
on-ground conservation outcomes.
• Protection and restoration of riparian
vegetation has been promoted through
a number of means; including large
scale weed-control programs, riparian
management agreements, and financial
incentive programs.
Description
From an ecological perspective, riparian
land is any land that adjoins, regularly
influences, or is influenced by a body of
water. It includes the land immediately
alongside rivers, areas surrounding lakes,
and wetlands and floodplains that interact
with rivers during floods. The widths of
riparian zones vary, and do not correlate
with the width or size of the stream143. In
small, upland streams, the riparian zone
can be greater than 100 m in width, and
may narrow further downstream, while in
floodplain reaches the zone may be much
wider144.
Riparian zones are important as they
support the ecological integrity of both
aquatic and terrestrial ecosystems, and
provide essential ecosystem services145.
Riparian zones harbour distinctive species
pools, so protecting riparian vegetation
within terrestrial reserves is an effective
means of increasing the number of
species protected on a regional basis146.
Large fallen branches or trunks from
riparian vegetation form key woody habitat
areas for many fish and invertebrates,
and influence the shape of the river
substrate (see IW2 In-stream and
Wetland Habitat). Riparian vegetation
also maintains the condition of aquatic
ecosystems by providing bank stability
and thereby minimising erosion, filtering
sediment and processing nutrients from
the catchment (particularly nitrogen), and
providing shade which moderates water
temperature. Riparian zones therefore
help to buffer aquatic ecosystems from
modified land use and disturbances within
the catchment147.
The relationship between aquatic
ecosystems and riparian zones is
reciprocal, as regular flooding is required
for recruitment of most riparian species in
floodplain ecosystems. Similarly, organic
matter from riparian vegetation is a major
source of food for in-stream biota, but
riparian zones may also benefit from the
nutrients and energy that aquatic systems
provide148.
Riparian zones provide a number of
other benefits to terrestrial ecosystems.
During droughts the proximity of riparian
vegetation to water also means it may
be the only place where plants have new
growth, flowers or are producing seed.
In catchments that are largely cleared,
riparian vegetation is often the only native
vegetation remaining149. Degradation of
native riparian vegetation is listed as a
potentially threatening process under the
Flora and Fauna Guarantee Act 1988150.
Riparian zones have always been useful
to humans; easy access to water and
fertile soil make them inherently useful to
agriculture, but they are also important
transport corridors, have high recreational
values and cultural and spiritual
significance. Administrative definitions
of riparian land differ from the ecological
context, which may change with time.
There are currently about 30,000 km of
Crown water frontages along rivers in
Victoria, which are often of 20 m width,
although this varies with location151.
About 22,000 km is of these frontages are
abutted by freehold land, and a sizeable
proportion of this length is licensed to
adjacent owners, mainly for grazing152.
The remaining 8000 km of riparian land
is in state forest or national parks. A high
proportion of lake fringes are also in public
ownership; this was estimated as being
80–85% of lake fringes in 1988153.
Extensive clearing of many catchments
and stock access to streams has resulted
in the condition of riparian vegetation
being moderate to poor across much
of the State. Wetland drainage has also
caused widespread loss of wetland
vegetation. Declining vegetation quality
is now the key driver of vegetation loss,
rather than broad-scale clearing (See Part
4:2 Land and Biodiversity). Weeds also
degrade the quality of riparian vegetation
by strangling native plants, out-competing
native species and altering ground
conditions, preventing the regeneration of
native species and reducing biodiversity.
Important riparian weeds include willow
(Salix spp.), blackberry (Rubus fruticosis
aggregate) and phalaris (Phalaris
aquatica)154. Willows were historically
planted for aesthetic reasons and,
especially from the 1950s,155 for the control
of bank erosion. As recently as the late
1980s, most drainage trusts and river
management boards still used willows in
erosion control works156. Both willow and
blackberry are now recognised as weeds
of national significance157.
This section reports on the riparian zones
of rivers and streams. The importance of
groundwater to baseflow to many rivers in
Victoria means groundwater is likely to be
similarly important to riparian vegetation.
Vegetation is also an essential component
of wetlands and its condition will in future
be reported through the Index of Wetland
Condition.
Objective
Protect and restore continuous corridors
of native riparian vegetation for rivers
and wetlands, to protect and improve
the health of aquatic and terrestrial
ecosystems.
State
Indicator IW7 Condition of riparian
vegetation of major rivers and tributaries
In 2004, riparian vegetation assessed by
the Index of Stream Condition (ISC) was in
good condition along 14% of reach length
assessed, with 54% in moderate condition
and 32% in poor condition158.
Six basins had 30% or greater of reach
length with riparian vegetation in good
condition, with the East Gippsland, Snowy,
Thomson, and Otway Coast basins being
in best condition (see Figure IW3.1). In
contrast, the Avoca, Bunyip, Corangamite,
Portland Coast and Millicent Coast basins
had no reaches with riparian vegetation in
good condition, and a further 17 basins
had less than 15% of reach length in good
condition. In five basins (Corangamite,
Portland, Millicent, Hopkins and Barwon),
more than 60% of riparian vegetation
was in poor condition. The vegetation in
poorest condition was generally found
in the lowland areas, where extensive
clearing has occurred159. The 2003
bushfires damaged riparian vegetation
in the Upper Murray basin, affecting the
condition assessment160.
Important aspects of riparian vegetation
captured in the ISC are width and
connectivity, and the quality, quantity and
structure of the vegetation161. Included
in the assessment of riparian vegetation
are estimates of width and longitudinal
connectivity, presence of large trees
and understorey species, presence of
organic litter, weeds and fallen timber,
recruitment, and tree canopy162. A rating
is produced by comparing the measured
condition to the ecological vegetation
class (EVC) benchmark. ‘Good condition’
means relatively intact and healthy native
vegetation, whereas ‘poor condition’
signifies little native vegetation remaining.
Longitudinal connectivity
Longitudinal connectivity provides an
important guide to the condition of
riparian vegetation. Across Victoria,
just over one-third (36%) of streamside
zones were considered to have riparian
vegetation with good longitudinal
connectivity. The forested reaches of the
upper catchments generally had better
longitudinal connectivity than in lowland
areas. The basins with best longitudinal
connectivity of riparian vegetation were the
East Gippsland, Snowy, Tambo, Mitchell
and Thomson basins, with the Yarra and
Hopkins basins also ranked highly.
Nearly half of all reach length assessed
(46%) had riparian vegetation with poor
longitudinal connectivity, and 20% was
considered to be in moderate condition.
The poorest condition reaches were found
mostly in basins to the west of the State,
particularly the Millicent Coast basin,
where land clearing left all reaches with
poor connectivity.
Weeds
Presence of weeds is also an important
indicator of the health of riparian
vegetation. In 2004, weed cover was
assessed in the ground, shrub, and tree
layers. Across Victoria, ground layerii
vegetation has been more degraded
by weeds, such as phalaris (Phalaris
aquatica), rye grass (Lolium spp.) and
thistles, than shrubiii and tree layeriv
vegetation (see Figure IW3.2). Statewide,
27% of reaches had a ground layer in
good condition (i.e. few weeds), whereas
82% and 92% of reaches were in good
condition in terms of shrub layer and
tree weeds respectively. However, tree
and shrub weeds such as willow and
blackberry have a more detrimental impact
than groundcover weeds.
Only six basins had more than 50% of
reaches assessed with ground-layer
riparian vegetation in good condition in
terms of weeds, whereas 28 basins had
at least 50% of shrub-layer vegetation
in good condition, and all basins had at
least 50% of tree-layer vegetation in good
condition.
The basins with fewest ground-layer
weeds were the arid Mallee basin and
the forested Mitchell and East Gippsland
basins, whereas cleared catchments
tended to have more ground-layer weeds.
Basins with shrub and tree layers that
scored moderate or poor for weeds
tended to be central or eastern basins
such as the Bunyip, Ovens, Upper Murray
and Kiewa, with infestations of blackberry
or willow.
The pressures that willow and the aquatic
weed arrowhead (Sagitiaria graminea var.
platyphylla) place on inland waters are
described in detail below (see Indicator
IW8 and Box IW3.1, respectively).
Pressures
The main pressures on riparian and
wetland vegetation are clearing, altered
flow regimes, stock access to riparian
land, invasive species, wetland drainage,
pollution and climate change. Pressures
on riparian vegetation reported in other
sections are: altered flow regimes (IW1
Flow regimes, Implications); modifications
to in-stream habitat (IW2 In-stream and
wetland habitat, Implications); water
quality (IW4 Water Quality, Implications)
and climate change (IW6 Implications
of climate change for inland waters,
Implications).
Vegetation clearing
Many Victorian settlements were
established near inland waters to gain
easy access to water and because of
the fertile soils on floodplains. This has
resulted in extensive removal of riparian
vegetation in some areas, such as the
agricultural areas of the lower Werribee
and Goulburn basins. Damage to riparian
vegetation is still occurring in areas
associated with residential development
and the appeal of water views.
Recreation activities along rivers and in
wetlands, such as high-speed boating,
have contributed to bank erosion and
the loss of habitat for riparian vegetation.
Recreational activities have also led to the
removal of riparian vegetation to enable
access for swimming, boating and fishing.
Stock access to riparian land
Domestic stock, particularly cattle, favour
riparian frontages and if uncontrolled
prefer to spend much of their time along
streambanks and in the water. The
pressure that uncontrolled domestic
stock grazing places on riparian zones
has been well documented, but it
persists on both public and private land
throughout Victoria, including the Barmah
and Gunbower forests165. Uncontrolled
stock access to riparian zones results in
erosion and loss of riparian vegetation.
Trampling and grazing of river and wetland
banks destabilises banks, as bare soil
on streambanks and compacted walking
tracks are prone to erosion166. Other
pressures caused by uncontrolled stock
access to streams are the introduction
and spread of exotic plants, inhibition of
native vegetation, soil compaction, lack of
regeneration of native vegetation, loss of
the buffering effect of riparian vegetation167
and the addition of nutrients through dung
and urine168.
Investigations by catchment management
authorities indicate that fenced stream
frontages were in significantly better
condition than those left unfenced,
reflecting the impact of stock access169.
Cattle grazing on the floodplain, which
reduces groundcover and increases seed
predation by ants170, has been described
as one of the causes of low recruitment
of River Red Gums. Restoration work
has shown that, even in drought, once
riparian areas are fenced, River Red Gum
recruitment is possible.
Indicator IW8 Extent of willows
across Victoria
Watercourses dominated by willows
exhibit reductions in numbers and diversity
of invertebrates, fish and native plants.
Some of the reasons for this include:
• Willows have lower habitat value than
native riparian vegetation. Fewer insects
results in fewer insectivorous birds and
less food for fish
• Willows dry out streams and wetlands
by using more water than the native
vegetation they replace
• Stands of willow exclude native
vegetation below the canopy due to
shade and dense roots
• Willows drop all their leaves in autumn,
creating a huge quantity of organic
material, followed by several months of
very little leaf litter. The biota of Victoria’s
inland waters are adapted to continuous
leaf fall
• Roots and foliage trap sediment, build
up the ground and divert flows into
banks. Eventually watercourses may
change course to flow around willows171.
Most catchments in the higher-rainfall
areas have well-established populations
of willow. Willows are commonly found in
the middle and lower reaches of rivers,
particularly those subjected to clearing
and channelisation works. Extensive areas
of willow in the upper catchment of the
Snowy River have recently been removed.
The extent and distribution of willow in
Victoria has not been fully mapped.
Willows are placing pressure on a
number of nationally significant wetland
communities in Victoria, including:
• Sedge-rich mountain swamp gum
(Eucalyptus aquatica) community
at Yellingbo, which is the habitat of
the nationally endangered helmeted
honeyeater (Lichenostomus melanops
cassidix)
• Alpine bogs and fens of the Bogong
High Plains
• Red gum floodplain vegetation on the
lower Ovens River172.
An example of another invasive aquatic
weed, Arrowhead, is shown in Box IW3.1.
Implications
Riparian vegetation in good condition
supports the resilience of aquatic and
terrestrial ecosystems, allowing recovery
from disturbance and maintaining
biodiversity. Riparian vegetation provides
habitat for platypus, water rats, frogs and
waterbirds, as well as the terrestrial adult
stages of macro-invertebrates. In some
ecosystems, riparian vegetation forms a
large proportion of remnant vegetation, so
it is locally significant.
An implication of degraded riparian
vegetation is that surrounding aquatic and
terrestrial ecosystems become vulnerable
to disturbances. Intact riparian vegetation
is a source of wood for in-stream habitat.
The exchange of nutrients and energy
from the riparian zone is central to the
functioning of river-floodplain systems178.
Without the ecosystem services that
riparian vegetation provides, these
ecosystems are less resilent. For example,
removal of riparian vegetation can result
in severe erosion that fundamentally
changes the stream ecosystem and
aids invasion by weeds such as willow,
threatening the survival of some native
species.
The resilience of biodiversity depends on
the availability of refugia from disturbances
such as flood and drought179. Removal
of riparian vegetation can reduce the
efficacy of drought and flood refugia for
in-stream and terrestrial flora and fauna.
The availability of refugia is expected to
become more important under climate
change, as there will be less water
available and the frequency of extreme
events is likely to increase.
Loss of connectivity or fragmentation
of riparian vegetation reduces the
capacity of species to disperse through
the landscape, and this may be of
fundamental importance in maintaining
viable populations180.
Loss of connectivity also reduces the
capacity of riparian vegetation to filter
catchment inputs. A reduction in the
extent and quality of riparian vegetation
has implications for the amount of soil
and nutrients that moves from cultivated
fields into waterways181. Riparian soils and
in-stream sediments can reduce nitrogen
loads to downstream environments
through microbial denitrification.
Degraded riparian vegetation reduces the
amount of habitat available for insecteating
birds and insect parasites that
protect agricultural land and crops from
damage. Even losing a small number of
birds can allow significantly more belowground
pasture grubs to survive and
become adults182. Further, a well-managed
riparian frontage can add significant
market value to a rural property.
Management responses
The importance of riparian land, pressures
on its condition and management
responses have been stated in a
number of studies over the past two
decades. Key documents include the
Land Conservation Council’s Rivers and
Streams Special Investigation (1991); The
Victorian Biodiversity Strategy (1997); The
Victorian River Health Strategy (2002) and
the Victorian Environment Assessment
Council’s River Red Gum Forests
Investigation (2007).
Improved management of riparian land
is complicated by mismatches between
administrative and ecological definitions
of riparian land, varying land tenure and
natural changes in the paths of rivers over
time183. Riparian Crown Land is dealt with
by two Acts: the Land Act 1958, and the
Crown Land (Reserves) Act 1978. The
Victorian River Health Strategy provides
a framework for managing riparian land
in this context, and the Victorian River
Health Program (see IW0 Introduction)
coordinates programs to improve the
condition of riparian vegetation.
Riparian vegetation is also protected
under Victoria’s Native Vegetation
Management – A Framework for Action.
Management responses to loss and
modification of native vegetation are
discussed in more detail in Part 4.2: Land
and Biodiversity.
Response Name
Individual projects performed as part of
regional river health strategies
Responsible Authority
Department of Sustainability and
Environment; catchment management
authorities
Response type
various
The Victorian River Health Strategy
outlines statewide targets for the
improvement of riparian vegetation.
Through the implementation of regional
river health strategies between 2002 and
2005, catchment management authorities
and Melbourne Water have made
substantial progress towards these goals
(see Table IW3.2).
Recommendation
IW3.1 More ambitious targets for the
rehabilitation of riparian vegetation
beyond 2011 should be considered for the Victorian River Health Program.
Response Name
Willow Control Program
Responsible Authority
East Gippsland Catchment Management
Authority
Response type
Program
Between 2002 and 2005, almost
$1 million was invested to eliminate
willow populations along 300 km of
the Wonnangatta, Dargo, Deddick and
Combienbar Rivers in the upper reaches
of the Snowy, Tambo and Mitchell
basins186. Natural regeneration of native
plants was encouraged and, in some
cases, supported by plantings of native
vegetation on the banks. Follow-up
surveys were conducted to confirm the
success of the removal program.
Response Name
RiverTender
Responsible Authority
North east CMA, North Central CMA
Response type
market-based instrument
RiverTender provides financial incentives
for landholders with river frontage to
improve river health and derive benefits
for their own property and the community.
This scheme, based on principles
established through the development
of BushTender (see Part 4.2: Land and
Biodiversity, LB1) addresses a market
failure in relation to ecosystem services
provided by healthy rivers. These
ecosystem services represent public
goods but there has been little financial
incentive for landholders to contribute to
improved river health.
Individuals or groups of landowners
prepare management plans that describe
measures to be undertaken, and the
funding required to complete the work
over five years. Funds are allocated
through an auction process to bids that
demonstrate the best value.
Pilot tenders in 2006 demonstrated a
positive response from the community.
The North East Catchment Management
Authority let a tender in the Ovens River
valley which resulted in management
agreements for an additional 800 ha of
riparian land, affecting 60 km of river
frontage. Another tender let in the North
Central CMA resulted in an additional
230 ha of land under management
agreements, affecting over 39 km of river
frontage.
Response Name
Special Investigation into Rivers and
Streams (1991)
Responsible Authority
Land Conservation Council (LCC)
Response type
Public land use planning
The LCC was directed by Government
in 1987 to investigate ‘the scenic,
recreational, cultural and ecological
values of rivers and streams in Victoria,
and make recommendations on the use
of these rivers and how their identified
values can be best protected’187. These
recommendations were subsequently
accepted by Government.
A key recommendation was that
stream beds and banks be used to
conserve native flora and fauna as
part of an integrated habitat network
across the State, and to maintain and
restore indigenous vegetation188. The
investigation recommended Crown land
water frontages be managed firstly for
conservation, then for recreation where
consistent with conservation, and then
for stock grazing provided there was no
conflict with conservation or recreational
objectives189. These recommendations
were subsequently endorsed through the
Biodiversity Strategy and Victorian River
Health Strategy190.
The LCC Investigation also recommended
that special status be conferred to rivers
of high environmental and community
value. This resulted in the establishment
of Heritage Rivers, Essentially Natural
Catchments and Representative Rivers.
The recognition of the high value of river
systems which remain relatively intact,
such as the Ovens and the Mitchell, is
of enduring importance given persistent
requests for additional water storages.
Evaluation of responses to
riparian vegetation
The importance of riparian vegetation
and pressures on its condition are well
documented. Substantial programs to
restore riparian vegetation are in place,
and the importance of partnerships
with adjacent landholders has been
recognised191. Progress has also been
made in formalising management
arrangements and responsibilities to
provide better long-term protection for
riparian areas192. Substantial change is
still required to transfer the understanding
and intention of management documents
into on-ground outcomes, as shown by
the low proportion of reaches statewide
with riparian vegetation in good condition.
Significant scope exists for reforming the
governance of riparian land, as outlined
by a recent review of the management of
riparian land in Victoria193.
Improving connectivity of remnant riparian
zones with high ecological values offers
opportunities to increase species richness
at a regional scale. It is a proactive,
strategic approach to increasing the
health of inland waters. Victoria is in the
fortunate position, compared to other
jurisdictions, to have extensive lengths
of stream bed and bank under public
ownership. This offers greater scope for
strategically improving connectivity, and
overall improvements in the management
of riparian land.
The endorsement of the LCC
recommendations 17 years ago, however,
has not resulted in a shift from the default
use of Crown Land water frontages
abutting private property for grazing,
to a conservation focus. As a result the
Land Conservation Council’s successor,
the Victorian Environment Assessment
Council (VEAC), recommended stronger
protection for crown land water frontages
in its River Red Gum Forests Investigation
by phasing out domestic stock grazing
from Crown Land water frontages over a
five year period194. The VEAC Investigation
also explored potential exceptions,
and incentives for both adjustment and
ongoing support for the positive actions
of many landholders. The Victorian
Government is currently considering
VEAC’s recommendations.
Improving riparian condition involves all
levels of government, private land holders
and CMAs. A broad range of responses
are either available or being developed,
and objective analysis of public and
private costs and benefits is necessary
to develop cost-effective investment
strategies. Activities that are within the
duty of care of private landholders and
managers as set out in the Catchment
and Land Protection Act 1994 should
be funded by the landholder. Activities
considered beyond the landholder’s
duty of care, however, are candidates for
support by government incentives.
The partnering approach that has been
so far successfully used to improve
riparian land management on private
land should be developed further.
Landholders often have limited financial
capacity to undertake works such as
fencing, to prevent uncontrolled stock
access to streams. Fencing allows
regeneration of riparian vegetation, and is
therefore essential to the sustenance of
riparian zones195. Financial incentives are
important, and would be assisted in the
long tem by the development of markets
for ecosystem services.
The immense value of riparian zones
to both inland waters and terrestrial
ecosystems demands commensurate
effort is exerted in managing them.
Momentum for improving the management
of riparian zones to form an integrated
habitat network across the State should
be re-established through the forthcoming
Land and Biodiversity White Paper, the
2009 renewal of Crown water frontages,
and through ongoing engagement with
riparian landholders across Victoria.
For further information
River Red Gum Forests Investigation
http://www.veac.vic.gov.au /
riverredgumfinal.htm
Review of Management of Riparian Land
in Victoria
www.publicland.com.au/pdf/Riparian%20
Report%20Exec%20Summary.pdf
Recommendations
IW3.2 The Victorian Government should
consider progressively extending VEAC
recommendations on phasing out
uncontrolled grazing of domestic stock
on Crown land water frontages to the
rest of Victoria, beginning with the 2009
licence renewal process
IW3.3 The Victorian Government should
update and streamline governance
arrangements to facilitate protection
and restoration of Crown Land water
frontages
IW3.4 The Victorian Government and
catchment management authorities
should consider regional-scale
connectivity of riparian vegetation in the
prioritisation of rehabilitation projects,
as part of forming an integrated habitat
network across the State.
IW4 Water Quality
Key findings
• Land clearing for agriculture and
urbanisation and contemporary land use
changes have led to major catchmentwide
changes, including erosion and
salinity, which have significantly affected
water quality in inland waters.
• In 2005, water quality objectives
for salinity were met at 68% of sites
across Victoria, and objectives for total
nitrogen, total phosphorus, and turbidity
were met at less than half the sites
monitored.
• Concentrations of total nitrogen and
total phosphorus posed a risk to
ecosystem health at about 80% of
lowland sites in 2005.
• Increasing trends in total nitrogen were
detected at over half the sites across
Victoria.
• River regulation, along with increased
nutrient inputs and low streamflow, are
now recognised as a major cause of
cyanobacterial blooms in rivers.
• The degradation of important receiving
waters such as Port Phillip Bay, Western
Port, Gippsland Lakes and the Murray
River is a major driver of water quality
improvement programs. Management
responses target a range of spatial
scales, from regional to the individual.
Description
Water quality is fundamental to the
ecosystem services that inland waters
provide, such as drinking water, cycling of
nutrients, maintenance of biodiversity, and
recreational and cultural opportunities196.
Poor water quality has serious implications
for the ecological health of inland waters,
biodiversity, and human and livestock
health.
As water quality degrades, inland waters
can fundamentally change, increasing
the cost of water treatment, marginalising
agricultural activity and reducing the
viability of other economic activities that
support community wellbeing. Inland
waters have been used as drains for the
catchment, degrading the ecosystem
services provided by high-quality water.
Water quality is influenced by many
other elements of the environment,
such as catchment processes and
management, flow regimes, riparian
vegetation and in-stream habitat. Even in
the driest parts of the landscape, most
activities affect water quality in some
way197. Land clearing for agriculture and
urbanisation, and contemporary land use
change has led to major catchment-wide
changes, including erosion and salinity.
Widespread application of fertilisers has
increased concentrations of nitrogen
and phosphorus in waterways. Research
undertaken nationally in 2001 showed
that phosphorus concentrations in inland
waters were three times higher than
pre-European estimates, while nitrogen
concentrations were estimated to be at
least double198. Point sources of pollution,
such as discharges from agriculture,
industry and wastewater treatment
plants, have also contributed to elevated
concentrations of phosphorus and
nitrogen in urban waterways.
In-stream pressures on water quality
include stock access to streams,
suspension of sediments and release of
nutrients, river regulation and extraction
of water, and the impact of invasive
species such as carp and willow. The
impacts of climate change will modify
these pressures, as reduced rainfall and
higher temperatures change catchment
hydrology and in-stream processes.
This section focuses on four key variables:
salinity, turbidity, nitrogen and phosphorus.
At a national level, these variables are
considered to be the most significant
river contaminants199. Only the water
quality of major rivers and tributaries is
examined. There are numerous other
variables that contribute to water quality,
such as pH, pesticides, heavy metals and
temperature, which may have particular
local or regional significance. Water quality
is also affected by interactions between
these components—for example; salinity
and temperature both affect the saturation
concentration of dissolved oxygen.
While some species are salt tolerant,
salinity can cause death or damage
to a wide range of plants and animals.
This in turn reduces habitat availability
and a reduction in biodiversity. Species
dependent on those directly affected by
salinity may be affected too200.
Turbidity provides a measure of
suspended solids in the water. Sediment
transport is a natural and important
function of inland waters, but excessive
quantities of sediment are an ecological
threat.
Nitrogen and phosphorus are essential
plant nutrients, but when waterbodies
become enriched with these nutrients
(i.e. eutrophication), excessive algal and
other plant growth, toxic algal blooms,
and more subtle changes to the species
composition of aquatic communities can
result201.
The statutory framework for the protection
of Victoria’s inland waters is set out in
the State Environment Protection Policy
(Waters of Victoria) (SEPP WoV) made
under the Environment Protection Act
1970. The SEPP WoV contains water
quality indicators and objectives that
protect the beneficial uses and values of
inland waters.
Water quality data are collected at over
200 sites through the Victorian Water
Quality Network, and monitoring programs
implemented by water corporations and
the Murray-Darling Basin Commission202.
Objectives
• Manage the catchment to ensure
that land use changes do not place
further pressure on inland waters,
particularly through control of point
sources of pollution and the improved
management of riparian zones and
wetlands
• Maintain robust ecosystems that
provide water purification, nutrient
cycling and transport services for
environmental and community benefit.
State
The following sections describe water
quality variables in terms of current status
and trends. The status of a water quality
variable at a site is expressed in terms of
whether the relevant SEPP WoV objective,
expressed as a concentration, was
attained or not during 2005. Attainment for
a given year can be influenced by climatic
factors such as rainfall and flow, as well as
changes in inputs from the catchment.
Non-attainment of an objective indicates
that the ecosystem is at risk. Rather than
signifying a “pass” or “fail”, this outcome
may then trigger an EPA risk-based
investigation, in which the level of risk is
further evaluated.
Trends that were detected over timeframes
ranging from five years to around
30 years203. In the following sections
trends are reported in terms of change
over the length of the time series at each
individual site. The methodology used to
detect trends takes climatic influences into
account204.
Due to the different data requirements,
different numbers of sites were assessed
for SEPP WoV attainment and trends in
each CMA area.
Indicator IW9 Trends and status of
salinity concentrations in rivers
Salinisation is a serious issue for many
lowland waterways throughout Victoria
and Australia. (see Part 4.2: Land and
Biodiversity, LB6 Salinity). SEPP objectives
for salinity are generally expressed in
terms of electrical conductivity (EC).
In 2005, EC objectives were achieved at
67% of sites across Victoria, indicating
that these sites were not at risk from
salinity. EC levels were lower in upland
sites (85% of 87 upland sites attained
SEPP objectives), compared to lowland
sites (55% of 139 sites attained SEPP
objectives)v.
EC objectives were attained at all sites in
two CMA areas (North East and Mallee)
and high rates of attainment were also
recorded in the Goulburn Broken and
West Gippsland CMA areas (see Figure
IW4.1). Only three sites were assessed
in the Mallee CMA area, so it may not be
representative of the entire area. In four
CMA areas (North Central, Port Phillip,
East Gippsland and Corangamite), EC
objectives were attained at 50–70%
of sites. In the Glenelg Hopkins and
Wimmera CMA areas, EC objectives
were attained at 23% and 20% of sites
respectively.
Increasing EC was detected at 20% of
sites, decreases at 42% of sites, and EC
remained stable at 38% of sites. Salinity
increased mainly in western Victoria, in
particular the Wimmera, Glenelg Hopkins
and Corangamite CMA areas, the western
part of the Port Phillip CMA area and a
number of locations in the North Central
CMA area205 (see Figure IW4.1).
EC had decreased at the site in the Mallee
CMA area, and at 80% of sites in the North
East CMA and East Gippsland CMA areas.
Indicator IW10 Trends and status of
turbidity concentrations in rivers
Many inland waters in Victoria are naturally
turbid due to high concentrations of
suspended sediment207. Turbidity is not
the same as the colour of water. Some
Victoria inland waters appear brown due
to the presence of tannins. These highly
coloured waters are usually clear, with very
low levels of suspended sediments and
turbidity208.
In 2005, turbidity objectives were attained
at 43% of sites across Victoria, indicating
that these sites were not at risk from
turbidity. Levels of attainment of objectives
were similar for upland (45% of 95 sites
met the objectives) and lowland sites (42%
of 141 sites met the objectives)vi.
The Glenelg Hopkins and East Gippsland
CMA areas had the highest levels of
attainment in 2005, with 93% and 70%
of all sites assessed attaining turbidity
objectives respectively (see Figure IW4.2).
In five CMA areas (Wimmera, NorthCentral, West Gippsland, Port Phillip and
North East), between 39% and 60% of
sites attained turbidity objectives in 2005.
The lowest levels of attainment were
observed in the Corangamite, GoulburnBroken and Mallee CMA areas, although
once again the low number of sites in the
Mallee CMA area limits the significance of
this result.
Increases in turbidity were detected at
34% of monitoring sites, whereas 30%
showed lower levels and 36% remained
stable. Increases in turbidity were detected
at a majority of sites in the North East
CMA area and at over 70% of sites in the
Goulburn-Broken CMA area.
Separate studies have shown short-term
increases in turbidity in some catchments
in the North East CMA Area following the
2003 bushfires209. Erosion of sediments is
dramatically increased after fire. The largescale
fires that burned across the Victorian
high country in 2003-04 greatly increased
erosion in these areas, leading to poor
water quality and deposition of large
amounts of soil and other materials in
stream beds and lakes210. The bushfires of
2006-07 are expected to produce similar
impacts on turbidity in affected basins
(see Part 4.2: Land and Biodiversity, LB8
Fire in the Victorian Landscape).
Indicator IW11 Trends and status of total
phosphorus concentrations in rivers
In 2005, total phosphorus (TP) objectives
were attained at 29% of monitoring sites
across Victoria, indicating that 71% of sites
were potentially at risk from elevated TP
levelsvii. Levels of attainment were higher
in upland sites (44% of 84 sites met the
objectives) compared to lowland sites
(19% of 140 sites met the objectives). Low
levels of attainment in the Port Phillip CMA
area contributed to the low state total, due
to the relatively large number of sites in
this region (15% of 71 sites attained TP
objectives).
Low levels of attainment were recorded in
the North Central, Corangamite, Goulburn
and Mallee CMA areas (see Figure IW4.3).
East Gippsland had the highest level of
attainment (82% of all sites).
Total phosphorus concentrations
increased at 20% of sites, decreased at
42% of sites, and remained stable at 38%
of sites. Increases in total phosphorus
concentrations were detected at over half
the sites in four CMA areas: GoulburnBroken (80% of sites), Glenelg Hopkins
(73% of sites), North East (58% of sites)
and Port Phillip (56% of sites). The
increases were mostly minor, although
there were large increases at one site
in the Glenelg Hopkins CMA area and
another in the North Central CMA area212.
Large decreases were found at one site
in the Corangamite catchment, and a
number of smaller decreases were found
at sites in the Port Phillip, North Central
and West Gippsland CMA areas.
Indicator IW12 Trends and status of total
nitrogen concentrations in rivers
In 2005, 29% of monitoring sites attained
total nitrogen (TN) objectives across
Victoria, indicating that 71% of sites were
potentially at risk from elevated TN levelsviii.
Levels of attainment were higher in upland
sites (43% of 83 sites met the objectives)
compared to lowland sites (21% of 134
sites met the objectives). Low levels of
attainment in the Port Phillip CMA area
contributed to the low state total, due
to the relatively large number of sites in
this region (3% of 80 sites attained TN
objectives).
Levels of attainment were also particularly
low in the Corangamite CMA area, with
only 5% of sites meeting the objective (see
Figure IW4.4). In the East Gippsland, West
Gippsland North East and Glenelg CMA
areas, more than half of all sites attained
total nitrogen objectives. Only one site was
assessed in the Mallee CMA area and,
although this site attained the objective, it
may not be representative of water quality
in this area.
Increasing total nitrogen concentrations
were detected at 52% of sites, decreases
were detected at 18% of sites, and
concentrations remained stable at 30% of
sites.
Increasing total nitrogen concentrations
were detected at 70% and 40% of the sites
in the Corangamite and Port Phillip CMA
areas respectively; both CMAs had low
levels of attainment (see Figure IW4.4).
Increasing total nitrogen concentrations
were detected at more than 50% of
sites in the Glenelg Hopkins, North East
and Goulburn-Broken CMA areas. Total
nitrogen concentrations decreased in
the Wimmera CMA area, although only
four sites were reported. No data were
available for the Mallee CMA area.
Indicator IW13 Presence of
cyanobacterial blooms
Cyanobacteria are naturally present in
Victoria’s inland waters. Under certain
conditions, their populations can explode,
causing a potentially toxic bloom. Low
river flow has been established as the
primary trigger for cyanobacterial blooms,
while the amount of nutrients present
(in particular, phosphorus) controls the
size of the bloom215. River regulation
has been identified as a root cause of
cyanobacterial blooms, as weir pools
and low but continuous flows of water
effectively convert the river into a series
of shallow, thermally-stratified lakes in
summer216.
The number of cyanobacterial blooms
recorded has increased dramatically since
1990, although this has been largely due
to the improved scrutiny of water bodies217.
While data have historically been collected
by individual agencies such as water
authorities (see Table IW4.1), they are now
regularly reported on a statewide basis
(see Figure IW4.5). These blooms, which
are above health alert levels, are reported
by water authorities and local waterway
managers.
Pressures
All activities in the catchment can affect
water quality in some way. Sources of
pollutants are generally divided into two
broad categories: point sources (e.g.
from a pipe) and diffuse sources (from
many points throughout the catchment).
Pollutants can also be stored in, and
released from, the sediments of a water
body.
Understanding the pathways by which
these pollutants move from their source
to inland waters, the transformations they
undergo and their eventual fate within
inland waters, are important steps to
managing water quality.
Some parts of the catchment have much
stronger links to pollutant loads than
others220. Computer modelling of sediment
transport in selected catchments of the
Murray-Darling Basin concluded that
75% of the suspended sediment load
is produced by only 20% of the total
contributing area221. The effectiveness
of water quality management can be
improved by prioritising intervention in
areas with strong links to pollutant loads.
The pressure that pollutants place on
water quality is also determined by
the timing of their discharge to the
waterway. Infrequent, major flow events
may contribute almost the entire annual
pollutant load, and thus place most
pressure on the water quality of receiving
waterways. Under other circumstances,
for example during low flow periods, the
concentration of pollutants is of most
concern, and therefore processes that
increase pollutant concentrations during
this time place the greatest pressure on
water quality.
Pressures on water quality are also
reported in IW1 Flow regimes, IW3
Riparian vegetation, IW5 Aquatic fauna
and IW6 Implications of climate change on
inland waters.
In terms of sources of contaminants, one
of the best-studied regions in Victoria is
the catchment of the Gippsland Lakes,
which has been investigated as part
of improving water quality in the Lakes
(see Figure IW4.6). Intensive land uses
(e.g. irrigation and horticulture) generally
contribute greater amounts of nutrients
and sediment per unit area, but extensive
land uses (e.g. grazing/pasture, forestry)
dominate the contribution to total loads.
As land uses intensify, total nutrient and
sediment loads are likely to increase
unless management is improved.
Salinisation
Land use changes, such as the
replacement of deep-rooted, native
vegetation with shallow-rooted crops and
pastures and irrigated agriculture, result in
stored sub-surface salts being mobilised
by rising groundwater. This process has
resulted in the dramatic expansion of land
and water salinisation (see Part 4.2 Land
and Biodiversity, LB6 Salinity).
Salinisation presents a direct threat to
groundwater-dependent wetlands where
irrigation and land clearing have raised
saline watertables, where saline irrigation
tailwaters have been disposed into
wetlands, or where estuaries have been
artificially opened to the sea. Salinity may
also be caused by evaporation in surface
waters223.
The rainfall deficits and higher
temperatures experienced over the past
11 years have contrasting effects on
salinity. Low rainfall reduces the rate of
recharge of saline groundwater levels,
and hence reduces the discharge of
saline groundwater to surface waters. On
the other hand, higher evaporation rates
concentrate the salt already in surface
waters. Salinisation will remain a latent
threat as groundwater levels will rise again
with heavy rainfall or flooding events.
Indicator IW14 Use of artificial fertilisers
Fertiliser is a key input for many of
Victoria’s agricultural enterprises (e.g.
beef, dairy and sheep), as it has a
strong influence on pasture production
and profitability (see Part 4.2: Land and Biodiversity).
In 2000-01, approximately one million
tonnes of phosphorus, nitrogen and
potassium fertilisers were applied across
Victoria. Soil nitrogen levels have also
increased through the cultivation of
pasture and grain legume crops, which
are able to bilogically fix atmospheric
nitrogen. Leaching of excess nitrogen
through the soil profile is the most
widespread cause of soil acidification.
Based on analysis of fertiliser use
using the Australian Stocks and Flows
Framework, it was estimated that a
threefold increase in the application of
artificial fertilisers has occurred since the
1960s which reflects the intensification of
agricultural practices over this period224.
Urbanisation
The Melbourne region is the most
urbanised part of Victoria, and it is where
the water quality impacts of urbanisation
are most obvious. A computer model
of the Port Phillip catchment shows that
urban areas make up less than 25% of
the catchment, yet contribute around 50%
of the catchment’s nitrogen loads225 to
Port Phillip Bay. Metropolitan Melbourne
occupies 210,000 ha; its urbanised area
has doubled between 1971 and 2004
(see Part 4.2: Land and Biodiversity,
Contemporary land use change). Further
urban growth is predicted to increase
nitrogen loads to Port Phillip Bay by up to
260 tonnes a year by 2030226.
Urban stormwater is the most significant
source of pollution to Melbourne’s rivers,
creeks and wetlands227. Stormwater
contains elevated levels of sediment,
nitrogen and phosphorus, as well as
other contaminants such as metals,
hydrocarbons and pathogens. The
expansion of urban, industrial and rural
residential areas has led to an increase in
paved areas, producing higher velocities
and volumes in runoff water, which
increases the risk of channel erosion.
Rapid, direct transport of these pollutants
by the drainage system amplifies the
pressure placed on receiving waters. Point
sources of pollution in urban areas include
outlets from sewage treatment plants,
intensive animal industries, irrigation and
stormwater.
Wastewater treatments plants are
generally a major point source of pollution
but in Melbourne the major treatment
plants discharge to Port Phillip Bay and
Bass Strait, rather than to inland waters
(see Part 3.2: Water Resources; Part 4.4:
Coasts, Estuaries and the Sea). In recent
years, increased recycling has reduced
the volume of wastewater discharged
directly to rivers (see Part 3.2: Water
Resources).
Internal loading
Most of the phosphorus and nitrogen
found in rivers, storages and estuaries
is located in the bottom sediments
eroded from the surrounding landscape
since catchments were cleared228.
Nutrients released from the sediment
can accumulate in the overlying water
column when the water column is stratified
and particularly when the bottom waters
become anoxic. These processes are
more common under low-flow conditions,
and in deep water such as reservoirs. The
combination of increased erosion and the
construction of large impoundments have
increased the scale of this pressure.
Bushfires
The pressures that bushfires exert on
water quality, such as increases in
turbidity, sediment and nutrients and
decreases in dissolved oxygen, are most
intense in the short term. A post-fire flood
in the Ovens River in 2003 produced a
sediment slug that increased turbidity
enormously in (70,000 NTU,ix compared
with a normal level of less than 10 NTU)
and suspended solids (33,000 mg per litre
compared with less than 6 mg per litre).
Dissolved oxygen concentrations declined
to 0.1 mg per litre, which is approximately
10% of the concentration at which fish
deaths occur229. The loss of water quality
in this event was temporary as the
sediment slug moved quickly downstream.
Up to 100% of fish populations in the
upper reaches of the Ovens River may
have been killed by post-fire sediment230.
Three years after the fires, river health,
measured in terms of the condition of
macro-invertebrate communities, had not
fully recovered at a number of sites231.
Nutrient and sediment loads received
by storages and estuaries may be
significantly higher than normal following
bushfires, contributing to long term
water quality problems and confounding
achievement of regional water quality
targets.
Fire suppressant chemicals that enter
waterways can cause fish kills and
affect nutrient concentrations. As more
sunlight reaches waterways following the
destruction of riparian vegetation, this
causes in-stream temperature ranges to
fluctuate, affecting in-stream biota and
dissolved oxygen levels.
Recommendation
IW4.1 Government and catchment
management authorities should
continue to promote and encourage the
uptake of current best practice land use
management to minimise diffuse water
quality pollution throughout Victoria.
Implications
The implications of poor water quality
are likely to be greatest in lowland rivers
and wetlands, water storages and weirs.
These areas are particularly susceptible
as they are the receiving environments
for substantial catchment outflows where
there are multiple point sources or diffuse
sources of nutrients. They are also often
sites where flow velocities are low and
residence times are high, providing the
opportunity for nutrient-rich sediments to
accumulate232.
Important coastal environments such
as Gippsland Lakes, Port Phillip Bay
and Western Port have been degraded
by pollutants in catchment inflows (see
Part 4.4: Coasts, Estuaries and the Sea).
The water quality of the River Murray
also degrades downstream, which has
implications for the health of the Coorong
in South Australia and Adelaide’s drinking
water supply. Without intervention,
reduced flows and increased salinity will
result in Adelaide’s main water supply
failing World Health Organisation levels
two days in five within 20 years233.
Biodiversity
Turbidity reduces light and consequently
the ability of aquatic plants to
photosynthesise and makes it more
difficult for animals to live within the
waterway, particularly those that are visual
predators. At very high levels, suspended
sediment can clog and damage fish gills
and the filter-feeding apparatus of animals
such as mussels.
Sediment contaminated with heavy metals,
nutrients and toxic organic compounds
may cause a loss of biodiversity through
the direct impact of toxicants or indirectly
through cyanobacterial blooms. Largescale
sediment deposition can bury entire
reaches, replace diverse river habitats
with uniform sand beds (sand slugs, and
create shallow flow areas that are subject
to greater temperature extremes and the
risk of invasion by aquatic weeds.
Salinity can have a range of lethal and
non-lethal effects234 leading to reduced
biodiversity and habitat availability.
Most freshwater organisms can tolerate
a certain level of salinity, with some
organisms found in freshwater known
to thrive in more saline environments235.
Some freshwater fish and crustaceans
are even diadromous, moving between
freshwater, estuarine and even marine
environments. Studies into the sensitivity
of frogs showed that wetland salinity did
not appear to limit their occupancy below
3,000 ECx, after which it declined rapidly.
No amphibians were detected where
salinity exceeded 6,000 EC236. Salinisation
of wetlands regularly causes salinity in
excess of these levels, indicating that frog
populations would be severely affected237.
The effects of salinisation on riparian
vegetation include lower species-richness
of native herbs and shrubs, and less cover
of native species, compared to freshwater
wetlands238. Four of 11 Ramsar-listed
wetland areas were at risk of salinity and
shallow groundwater in 2000 under the
worst-case scenario assessed by the
National Land and Water Resources Audit
(2001), and up to eight would be at risk by
2050, although this assessment may not
incorporate climate change projections239.
Few studies have examined the effects
of salinised rivers or wetlands on
biodiversity or ecosystem services240. The
implications for salinity on inland waters
are also discussed in Part 4.2: Land and
Biodiversity, LB6 Salinity.
One of the major impacts of high levels
of nutrients on inland waters is the overgrowth
of algae and in-stream vegetation.
This greatly increases the risk of algal
blooms capable of killing fish, damaging
water supplies and preventing recreation.
Biodiversity can be adversely affected
as wetlands and waterways become
dominated by algae and weeds that thrive
in high-nutrient conditions, replacing the
more diverse, indigenous species adapted
to low-nutrient conditions. Death and
decomposition of excessive in-stream
growth can reduce oxygen levels to the
detriment of aquatic biota.
Following the immediate impacts of
bushfires, loss of vegetation can lead
to an ongoing, large influx of eroded
sediment and organic matter entering
waterways and reducing water quality. As
the organic matter decomposes, it can
raise nutrient concentrations and lower
dissolved oxygen concentrations, affecting
fish, insect larvae, aquatic mammals
and waterbirds. It can also increase
algal growth and reduce drinking water
quality241.
Lower quality water for consumption
In a water supply context, water quality
is of vital importance and has its own
regulatory framework and monitoring
programs. The data presented in previous
indicators are not relevant to consumptive
uses. Due to Victoria’s reliance on
surface water sources, however, surface
water quality does have implications for
consumptive uses.
Loss of water quality in surface water
sources can have significant economic
implications, particularly for communities
that rely on rivers and streams to
provide domestic water. For example,
it is estimated that water treatment in
the Murray-Darling Basin will cost the
community an additional $7m per year by
2050242.
Higher salinity accelerates corrosion and
can damage infrastructure, such as roads
and bridges243. It also affects soil, plant
and livestock health and can therefore
reduce agricultural productivity.
Cyanobacterial blooms create pungent
smells and make waterways unappealing
for recreational activities244. Waterways
affected by blooms are unsuitable for
agriculture use and many stock deaths
have been reported245. Large blooms in
reservoirs can cause major difficulties
for drinking water supply, as they block
filters and produce tastes and odours
that are difficult to treat.246 Some species
of cyanobacteria can produce toxins that
are dangerous to animals and humans
if they are consumed or possibly even
touched247.
Sediment deposition following fires has
significant implications for water supply to
towns depending on river water. Treatment
plants struggle to process the additional
sediment load and water supplies may
be interrupted while additional filtration is
applied. Where existing stored supplies
are limited, additional water may need
to be trucked in to supplement supplies
and dilute the sediment to a treatable
concentration. The treatment of water
from rivers affected by post-fire sediments
requires ongoing management because
sediment deposited on the river bed is resuspended
each time flow increases.
Reduced opportunities for recreational
and cultural activities
Cultural services are affected by keeping
people from swimming, boating, and
otherwise enjoying inland waters affected
by potentially toxic cyanobacterial blooms.
These blooms also impose costs on
recreational and tourism operations.
Climate change
Implications of climate change on water
quality are discussed in IW6 Impacts of
Climate Change on Inland Waters.
Infrastructure
There are also implications for water
resource management. Water supply
dams can lose capacity due to sediment
deposition, which requires costly
treatment. Sediment build-up can
exacerbate flooding where channels have
become shallower and outlets blocked.
This increases flood magnitude and
frequency, increasing the risk of damage
to buildings, roads, bridges, pipes,
farmland and other infrastructure.
Management responses
Reducing catchment-based pollution and
ensuring that land use changes do not
place further pressure on inland waters is
a fundamental objective of water quality
management. A broad range of measures
are currently implemented across a range
of agencies and organisations to manage
water quality in Victoria, reflecting the
diversity of both sources and solutions to
water quality problems. Responses that
improve other aspects of the condition
of inland waters (see preceding sections
on riparian vegetation, bank stability and
flow regimes) and the land (see 4.1 Land
and Biodiversity, Management responses
sections) are also likely to improve water
quality.
Response Name
State Environment Protection Policy
(Waters of Victoria)
Responsible Agency
Environment Protection Authority
Response Type
Policy
The State Environment Protection Policy
(Waters of Victoria) (SEPP WoV) sets out
the statutory framework for the protection
of Victoria’s waters. The water quality
objectives prescribed in the SEPP (WoV)
have been used in the planning and
guidance of other programs. For example,
the Victorian River Health Program
expresses its water quality targets in terms
of SEPP (WoV) objectives, and they are
widely used by catchment management
authorities.
Across Victoria, there are 35 attainment
programs associated with the SEPP
(WoV). These are mainly implemented by
catchment management authorities and
water authorities. Attainment programs
have been implemented to varying levels.
The Environment Protection Authority
is reviewing the implementation of the
SEPP framework and the potential
impact of climate change on reference
site condition. Recent advances in water
quality condition assessment should be
investigated, including ecosystem function
indicators and risk-based approaches.
Recommendation
IW4.2 State Environment Protection
Policy (Waters of Victoria) should be
reviewed to ensure consistency with
best scientific practice in the context of
a changing climate.
Response Name
Gippsland Lakes Future Directions
Action Plan (2002)
Responsible Agency
Department of Sustainability and
Environment
Response type
Management Plan
The Gippsland Lakes have suffered from
frequent cyanobacterial blooms. Over
the years an evolving series of plans to
improve water quality in the Gippsland
Lakes has been produced, culminating in
the Gippsland Water Quality Action Plan (2005).
A centrepiece of these plans has been
a target to reduce nutrient loads by 40%
by 2022248, established in the Gippsland
Lakes Future Directions Action Plan
(2002). Substantial investment, of $12.8
million between 2002 and 2006, and
$6 million from 2006 to 2009 has been
committed to achieving this target.
However, modelling indicates that, if
current management practices are
implemented, only a 12-20% reduction
in nutrient loads will result249. Along with
ongoing implementation of management
practices, research is being conducted
to improve management practices so the
original target is achieved.
A separate target of a 40% reduction
in nutrient loads from the Macalister
irrigation district was also established in
2002, due to the importance of irrigation
to total nutrient loads (see Figure IW4.6).
This target has been met four out of the
past five years, with lower streamflow
contributing to this reduction. Overall,
the uncertainty of both modelled load
estimates and the measurement of
actual loads, combined with unusual
climatic conditions which have resulted
in droughts, floods and bushfires, have
to some extent confounded accurate
measurement of progress250.
Response Name
Victorian Planning Provisions Clause 56
Responsible Agency
Department of Sustainability and
Environment
Response Type
Planning scheme
Clause 56 is the Residential Subdivisions
component of the Victoria Planning
Provisions (VPP) which provides the basis
for all local council planning schemes in
Victoria251.
The provisions of Clause 56, which
apply specifically to new residential
developments, include objectives for
integrated water management, mandated
performance objectives for urban
stormwater management, and improved
site management standards. The current
focus of the Clause 56 implementation is
the stormwater management objectives,
although water shortages are also driving
interest in integrated water management.
A major challenge in the implementation
of Clause 56 is industry capacity252.
Successful implementation of urban
stormwater management measures
requires understanding and technical
capacity across a broad range of
disciplines and organisations. Insufficient
knowledge and skills across the sector
could ultimately lead to ineffective
systems, undermining the credibility
and stakeholder acceptance of new
techniques.
Industry capacity is being addressed
through the Clearwater capacity building
program. Initiatives of Clearwater include
an officer to help local councils implement
Clause 56, as well as a website and
training seminars. While Clause 56 applies
statewide, Clearwater is currently limited to
the Melbourne region.
Clause 56 provisions do not mandate
stormwater quality objectives for nonresidential
development or renovations.
Therefore there is scope for broadening
the range of developments to which
stormwater quality objectives apply and
extending capacity building programs
into regional Victoria. Clause 56 might
also be used to promote integrated water
management practices.
Recommendations
IW4.3 Further degradation of urban
waterways should be reduced by
applying similar integrated water
management provisions to nonresidential
urban subdivisions
as currently apply to residential
subdivisions under Clause 56 of the
Victoria Planning Provisions with
continuation and expansion of capacity
building programs for council and
development industry practitioners.
IW4.4 The review of water quality
management objectives based on
reductions in contaminant export
compared to a base case (e.g. stormwater
management objectives for residential
development) should factor in continued
intensification of urban and rural land
uses. Continued research and innovation
to improve and develop management
practices should be encouraged.
Response Name
Waterwatch in Victoria
Responsible Agency
Waterwatch
Response Type
Community Engagement and water
quality monitoring
Waterwatch is a national, communitybased
water quality monitoring network
that has been operating in Victoria for
15 years253. Waterwatch is based on a
network of regional and local coordinators,
hosted by various catchment management
authorities, water authorities and local
government254. In 2004, Waterwatch
employed 45 people in Victoria255.
An ongoing challenge for Waterwatch
has been improving the quality of data
captured so that it can be used to inform
management decisions. This has been
addressed through an ongoing process
to improve data quality control and
assurance and emphasise the quality of
the data set in terms of completeness and
representativeness, as opposed to sample
accuracy.
Over time, Waterwatch has evolved into a
diverse program that provides community
education, collects water quality data and
builds social capital. It is an important
link between a range of regional and
local organisations, including catchment
management authorities, water authorities,
local government, private business, the
scientific community and the education
sector. Opportunities for integrating
Waterwatch with other community and
government monitoring programs should
be pursued.
Evaluation of responses
to water quality
Water quality management requires
regional-scale management, but like
water consumption, it is also one aspect
of inland waters that is within the means
of each individual to influence. Current
management responses address both
ends of this spectrum.
In addition to the statewide framework
provided by the SEPP, the Victorian
Nutrient Management Plan (1995) was
an important step in the establishment of
regional-scale water quality management.
This plan required each CMA region to
produce a nutrient management plan.
Environmental degradation of major
receiving waters such as Gippsland Lakes,
Port Phillip Bay and the River Murray has
been a major driver of catchment water
quality improvement programs. The Port
Phillip Bay Environmental Management
Plan (2002) recommended a 1000 t
reduction in nitrogen loads to Port Phillip
Bay. Half of this reduction was to be
achieved through improvements to the
Western Treatment Plant at Werribee,
and the other 500 t by reducing nitrogen
loads from the catchment. Melbourne
Water’s Waterways Water Quality Strategy
(2008) has committed significant funding
to improve water quality in the Port
Phillip and Westernport catchments,
with an estimated $92 million to be
invested from 2008 to 2013. Monitoring
which will determine progress towards
the catchment target is still in process.
Increasing urbanisation will continue to
increase nutrient loads to Port Phillip
Bay, highlighting the need for continuous
improvements to management practices
and the control of urban planning and
development.
In addition to the water quality variables
presented in this section, a vast range
of industrial and agricultural chemicals
end up in waterways. Some of these—for
example the herbicide atrazine—can
be toxic at very low concentrations
(see IW5 Aquatic Fauna, Implications),
while other contaminants persist in the
environment and accumulate in aquatic
biota. Detection of these chemicals in
itself poses a challenge. Establishing
toxic effects on biota, especially when
there may be synergistic or cumulative
impacts, is difficult and the subject of
current research. Support should be
given to research aimed at understanding
the levels of these toxicants in rivers
and creeks, contributing land uses and
impacts on aquatic ecosystems.
Long term datasets of known quality are
a vital resource for both scientists and
natural resource managers. In the context
of drought and climate change, with inland
waters varying beyond their usual range
of fluctuation, continuity of observations is
critical256.
For further information
Waterwatch Victoria
http://www.vic.waterwatch.org.au/
Water Quality attainment and trend
reports
http://www.vicwaterdata.net/
National River Contaminants Program
http://products.lwa.gov.au/products/
pk071328
IW5 Aquatic Fauna
Key findings
• Extraction of water, regulation of flow
regimes and alteration of habitat are
major pressures on aquatic fauna and a
primary cause of decreasing native fish
populations. Declining water availability
over the past 11 years is also affecting
the fauna of inland waters.
• Many species are now considered
threatened, including 21 freshwater and
estuarine fish species, 11 frog species
and 29 species of waterbirds.
• Macro-invertebrate communities
were found to be in good condition
across almost half of the reach length
assessed as part of the 2004 Index of
Stream Condition.
• The total index of abundance for
waterbirds in eastern Australia has
shown a declining trend over past
decades, with 2007 having the secondlowest
abundance on record.
• Implications of the decline in the native
aquatic fauna of inland waters include
the reduced survival and diversity
of species, and reduced ecosystem
function and ecosystem services.
• Providing environmental flows,
and maintaining and improving the
quality and connectivity of in-stream
habitat and riparian vegetation that
supports aquatic fauna through their
life history is essential to maintaining
the conservation status of threatened
species.
Description
Freshwater fauna contributes significantly
to Victoria’s biodiversity. Victoria’s
freshwater systems support two species
of freshwater mammals (the platypus
(Ornithorhynchus anatinus) and water
rat (Hydromys chrysogaster) over 100
species of waterbirds, 33 species of
amphibians, 46 species of freshwater
fish and an undetermined number of
invertebrate species (see Part 4.2: Land
and Biodiversity, LB3 Threatened species
and pest plants and animals)257. High
levels of endemism have been identified
but uncertainty remains over the current
and reference distributions of many of
Victoria’s aquatic fauna.
Aquatic fauna have intrinsic value and
are integral components of inland
waters. The other issues covered in
this part of the Report—flow regimes,
water quality, in-stream and wetland
habitat, riparian vegetation and climate
change—can impose major pressures on
aquatic fauna. Other pressures include
introduced species and recreational
fishing. Commercial fishing for native fish
species, including Murray cod (Macquaria
australasica), golden perch and silver
perch, is now banned in Victoria’s
inland waters except for some estuaries.
Because of their sensitivity to a range
of pressures, the condition of aquatic
faunal communities, in particular macroinvertabrates,
are used as measures
or ‘bio-indicators’ of the condition of a
freshwater system and sometimes of the
health of its surrounding catchment258.
The impact of these pressures is reflected
in the number of inland water-dependent
species considered threatened under
the Flora and Fauna Guarantee Act
1988, which includes 21 freshwater and
estuarine fish species, 11 frog species and
29 waterbird species.
This section reports the status of aquatic
fauna reliant on inland waters. Many
species of fish and waterbirds range
from freshwater to estuarine and marine
habitats, however, and so can’t be
excluded from this section. Estuarine,
coastal and marine fauna are further
reported in Part 4.4: Coasts, Estuaries and
the Sea. The overall status of biodiversity
including threatened species is reported in
Part 4.2: Land and Biodiversity.
Objectives
• Improve the conservation status of
Victoria’s aquatic fauna
• Limit the introduction of new exotic
species, and ensure no new exotic
species reach pest status
• To protect and improve the habitat of
the aquatic fauna of inland waters
• To strengthen the resilience of aquatic
fauna to current pressures including
climate change
State
Indicator IW15 Conservation status
of aquatic vertebrate and macroinvertebrate
fauna
Many species of aquatic vertebrate fauna
are considered threatened under the Flora
and Fauna Guarantee Act 1988. Further
information on the relative conservation
status of vertebrate species is provided by
the Advisory list of threatened vertebrate
fauna in Victoria – 2007xii (Advisory list)
(see Figure IW5.1).
A total of 21 freshwater and estuarine
fish species are listed as threatened
under the Act. Three species of native
fish (Agassiz’s chanda perch (Ambassis
agassizii), freshwater herring (Potamalosa
richmondia) and southern purple spotted
gudgeon (Mogurnda adspersa)) are
considered regionally extinct under
the Advisory list260. Seven species
are considered critically endangered,
including trout cod (Maccullochella
macquariensis) and silver perch (Bidyanus
bidyanus)261. Five species are considered
endangered, including freshwater
catfish (Tandanus tandanus), Macquarie
perch and Murray cod (Maccullochella
peelii peelii)262. A further six species are
considered vulnerable, two species are
‘near-threatened’ or likely to become
threatened in future, and there are
insufficient data to classify another two
species263.
Frog populations throughout Victoria have
declined and 11 out of a total 33 species
are considered threatened under the
Act264. The conservation status of the 17
amphibian species listed in the Advisory
list is summarised in Figure IW5.2.
Two species of turtle are considered
threatened under the Act; the Broad
Shelled Turtle (Chelodina expansa) is
considered endangered, and the status of
Murray River Turtle (Emydura macquarii) is
considered data deficient.
Twenty-nine species of waterbirds, out
of a total of around 100 species, are
considered threatened under the Act265.
Of these, 11 species generally inhabit
freshwater systems, 13 species prefer
coastal or marine environments2, and five
species may be found in both freshwater
and coastal environmentsxiii. The
conservation status of the 63 waterbird
species listed in the Advisory list is
summarised in Figure IW5.2.
Freshwater macro-invertebrates are a
diverse group of insects, crustaceans
and molluscs that include snails, yabbies,
water boatmen, dragonflies, stoneflies and
worms. The number of macro-invertebrate
species in Victorian freshwater systems
is unknown but is estimated to greatly
exceed the diversity of vertebrate fauna267.
In 1997, out of over 100 known species, 14
insects and 19 crustacean species were
identified as threatened in Victoria268.
Platypus is not listed as a threatened
species at present269. They are common
across their range, which extends
from tropical Queensland to southern
Tasmania270. A breeding population exists
as close to Melbourne at the mouth of
the Plenty River, 15 km from the city271.
Platypus is protected by law.
The water rat is also distributed widely
across eastern Australia, as well as Papua
New Guinea and a number of adjacent
islands272. It occupies a wide variety
of habitats and can persist in urban
areas273. The water rat is not considered
threatened274.
Indicator IW16 Observed versus
predicted presence of native fish species
There is general consensus that
many native freshwater fish have a
reduced distribution and abundance
when compared with distribution
and abundance prior to European
settlement275. In the Murray-Darling Basin,
it is estimated that fish communities are
approximately 10% of previous levels and
are in danger of further decline276.
Historically, few records for fish have
been entered into the Atlas of Victorian
Wildlife, which is the main repository on
information on the status and distribution
of animal species (see Part 4.2: Land and
Biodiversity, Indicator LB21). Information
on the condition of native fish communities
across Victoria is now collected through
the Sustainable Rivers Audit (SRA) which
is used for the Murray-Darling Basin. Data
for observed versus predicted presence
of native fish species are currently
available only for the northern basins.
The assessment of southern basins will
be completed in 2008. Observed data for
these basins were collected for the SRA
between 2004 and 2006. The predicted
species were those believed to have
been present in each basin under presettlement
conditions277 based on expert
knowledge, museum collections and
historical data.
With the exception of basins in the
Wimmera (5 species observed to
6 predicted), Goulburn (14 species
observed to 25 predicted) and Kiewa
(11 species observed of 16 species
predicted), only half or less than half of
the number of native species predicted
to be present were observed (see Figure
IW5.2). While the presence of fish in
sample locations will vary, the survey
results demonstrated consistently lower
numbers of native species captured
compared to those predicted under
reference conditions. This provides a
strong indication that native fish species
diversity, and hence community integrity, is
poor in these areas.
Indicator IW17 Abundance of native fish
compared to introduced fish
From 2004 to 2007, 23 out of 29 basins in
Victoria were assessed for the abundance
of native fish species. Two metrics are
reported here: numbers of individual fish
per species (abundance) and estimated
biomass of each species. Estimates of
biomass suggest the relative size of each
species.
Information on the condition of native fish
communities across Victoria is collected
by both Department of Sustainability
and Environment and Department of
Primary Industries, and through the MDBC
Sustainable Rivers Audit.
Overall, the surveys reported a greater
abundance in numbers of native fish (71%)
than introduced fish in Victoria’s rivers and
streams.
Basins south of the Divide contain species
that require a marine life-phase, whereas
these species are largely absent north of
the Divide279.
Since European settlement, several exotic
species of fish have adversely affected
native fish populations. They include
rainbow trout (Oncorhynchus mykiss) and
brown trout (Salmo trutta), which favour
cool upland streams and lakes, and were
stocked for recreational purposes280.
Most trout are now only stocked in
‘closed systems’ for recreational fishing.
Carp, oriental weatherloach (Misgurnus
anguillicaudatus), gambusia, goldfish
(Carassius auratus) and redfin perch
(Perca fluviatilus) are other significant
exotic species that prefer slow-flowing or
still water281.
In northern basins, just over half (52%) of
the fish captured were native. Abundance
of native fish was lowest in the Campaspe
basin, where only 21% of all fish captured
were native (see Figure IW5.3). Native
fish accounted for no more than than half
the fish captured in the Upper Murray
(37%), Goulburn (42%), Kiewa (43%)
and Mitta Mitta (50%) basins. In these
basins, cleared land, modified hydrology
associated with major water storages
and deliberate introduction of non-native
fish species for recreational fishing may
have favoured introduced fish. In 2007,
oriental weatherloach was recorded in the
Goulburn River for the first time282, having
spread a considerable distance along
the River Murray. The Broken basin had
the greatest abundance of native fish in
northern basins, with 74% of fish captured
being native.
The most common fish species in the
Loddon and Avoca basins were a complex
of native galaxiid species (Galaxia
spp.). Flathead gudgeon (Philypnodon
grandiceps) were most common in the
Wimmera basin and southern pygmy
perch (Nannoperca australis) were most
common in the Broken basin. Introduced
gambusia, otherwise known as the
mosquito fish, was the most common
species in the Campaspe, Kiewa and
Ovens basins, with brown trout the most
common species in the Upper Murray and
Goulburn basins.
Native fish accounted for less than 40%
of the overall fish biomass in each of the
northern basins. In six out of 10 basins,
native fish accounted for between 4%
and 11% of total fish biomass. These
were: Upper Murray (MDBC); Mitta Mitta
(MDBC); Avoca; Kiewa; Campaspe and
Wimmera basins. The Loddon (21%),
Ovens (23%), Goulburn (35%) and
Broken (37%) basins had relatively higher
proportions of native fish in the total
fish biomass. These results reflect the
abundance of introduced species, but
it should be noted that species such as
carp, rainbow trout and brown trout are
larger than most native fish. For example,
in the Avoca basin, introduced fish
sampled were on average 50 times larger
than native fish284.
Restocking programs (see IW5 Aquatic
fauna, Management responses) contribute
significant numbers of juvenile fish, but the
contribution of restocking to overall fish
populations has not been ascertained.
Historical and anecdotal records indicate
that the now endangered Murray cod was
once abundant throughout the Campaspe
and other basins which make up the larger
Murray-Darling Basin285. Commercial
catch data for Murray cod from NSW and
South Australia are believed to reflect the
Victorian situation and indicate a dramatic
decline in harvest between the 1950s and
the 1980s (see Figure IW5.4)286.
Commercial fishing for native fish species,
including Murray cod, golden perch and
silver perch, is now banned in Victoria’s
inland waters except for some estuaries.
Over recent years, according to surveys
conducted by DPI Victoria, there has
been increased angler reporting of Murray
Cod numbers, however there are no
baseline data available that clearly show
if the Murray cod population has further
declined over the last 10 years, or started
to recover.
In contrast, native fish accounted for 82%
of fish caught in the southern basins, and
in each basin at least half the fish captured
were native. The three basins with the
lowest abundance of native species were
the Maribyrnong (51%), Yarra (64%) and
Latrobe (66%). In the Snowy, Glenelg,
South Gippsland, Portland Coast and
Millicent Coast fbasins, 90% or more of
fish captured were native. The Millicent
Coast basin, in Victoria’s far west, was the
only basin in which all the fish captured
were native, but the sample size was
small (92 fish). However, not all species
captured were indigenous to the area,
with a small number of translocated carp
gudgeon (Hypseleotris spp.) identified,
whose normal range is the Murray-Darling
system.
The short-finned eel (Anguilla australis)
was the most common native species
present in the Barwon and Moorabool
basins. Eels were abundant in western
Victoria and were important species in
several lake systems. Canals and weirs
were used by indigenous people to trap
eels in the Lake Condah and Toolondo
lakes288. An estimated 50,000 eels died
in Lake Modewarre and another 5,000 in
Lake Bolac between October 2004 and
January 2006289. It is thought that drought
played a major role in these deaths290.
The most abundant species in individual
basins were Australian smelt (Retropinna
semoni), in the Tambo and Snowy basins,
and southern pygmy perch in the Glenelg
and Portland Coast basins yelloweye
mullet (Aldrichetta forsteri) in the South
Gippsland basin, and common Galaxias
(Galaxias maculatus) in the Bunyip basin.
The most common species captured in
the Millicent basin was the native Yarra
pygmy perch (Nannoperca obscura),
at 86% of all individual fish caught. The
proportion of biomass contributed by
native fish in southern basins was not
available.
Recommendation
IW5.1 The Victorian Government should
undertake regular, long-term, native fish
population surveys across Victoria.
Indicator IW18 – The condition of macroinvertebrate
communities of major rivers
and tributaries
Aquatic macro-invertebrates are routinely
used as indicators of the condition of
freshwater systems. They are relatively
sedentary, they spend at least part of their
life in aquatic ecosystems and are critical
to their functioning, and their response
to pollution and human disturbances is
relatively well understood291. Where land
use change and habitat modification
has been extensive, macro-invertebrate
communities show the greatest evidence
of impairment292.
Macro-invertebrate communities were in
good condition across 49% of the stream
reaches assessedxiv. Of the remainder,
32% were in moderate condition and 19%
in poor condition. Over half of the river
length assessed for macro-invertebrate
condition in Victoria (covering 7,138 km
and 506 reaches), has been modified.
Those areas with significant habitat
modification, flow regulation and poor
water quality have the macro-invertebrate
communities in poorest condition.
Samples can be taken only where
water is present, so sites dry at the time
of sampling were not included in the
condition assessment presented above.
As the dry sites are often in poor condition,
this may have skewed the results to show
better condition than actually existed.
Drying and isolated pools are included
in the assessment, which may explain
some of the lower scores of some basins.
Sampling protocols have been amended
to capture better data on dry sites293.
Changes in macro-invertebrate scores
in reference condition sites between
1998 (pre-drought) and 2004 (droughtaffected)
were identified by the EPA294.
Notwithstanding the constraints described
above, the number of edge habitat sites
meeting EPA objectives at reference
sites statewide decreased between 1998
and 2004. Macro-invertebrate condition
for riffle habitat sites, on the other hand,
tended to increase at reference sites
statewide over the same period. Low
flow conditions in riffle habitat, allowing
increased macrophyte and algal growth,
were to the advantage of some taxa. For
both riffle and edge habitat, little change
was noted in the upland forests, with
drought having the greatest effect on the
lowland forests and cleared hill regions.
Since this assessment, there have been
four more years of low streamflow, with
potentially greater impacts on macroinvertebrate
communities.
The macro-invertebrate assessments
were not always representative of the
basin as a whole. For example, the
majority of sites assessed in the highly
modified Bunyip basin were clustered
by chance in the forested upper parts
of the basin, resulting in a condition
assessment not representative of the more
developed parts of the basin295. Random
site selection is an important element of
monitoring program design but it can
lead to uneven coverage of sites across
a basin.
Macro-invertebrate communities in the
Mitchell, East Gippsland and Broken
basins were considered in best condition,
indicating that a significant number of
their rivers and streams are likely to be
close to reference condition (see Figure
IW5.5). The Mitchell and East Gippsland
basins are generally forested and sparsely
populated. Although sections of their lower
floodplain reaches have been cleared, a
narrow band of vegetation remains along
many streams, providing significant habitat
for macro-invertebrates in comparison to
other more extensively cleared basins.
Macro-invertebrate condition is also good
in unmodified upland streams.
Of the 28 basins surveyed, the Hopkins,
Avoca, Campaspe and Loddon basins
demonstrated the poorest macroinvertebrate
condition. For example, in
the Hopkins basin, 43% of reaches were
in moderate condition and 57% in poor
condition, indicating that a significant
proportion of rivers and streams in the
basin fall well short of reference condition.
All of these basins are highly modified,
with water extraction occurring for irrigation
and other consumptive purposes, little
to no vegetation in the riparian zones of
several rivers and significant clearing of
land for agriculture and rural settlements.
Large woody debris, an important habitat
feature for macro-invertebrates, was
sparse in many reaches of these basins
(see IW2 In-stream and wetland habitat).
Indicator IW19 the abundance of
waterbirds in Victoria
Victorian inland waters provide critical
habitat for indigenous and migratory
waterbirds. Waterbird communities
depend on a range of aquatic organisms
for food and can provide an indication of
changes to inland water biodiversity, as
well as ecosystem health. The abundance
(see Figure IW5.6) and distribution of
species is indicative of the condition of
individual species as well as waterbird
species collectively297.
Annual aerial surveys conducted across
eastern Australia from 1983 to 2004 have
provided information on the trends and
abundance of up to 50 waterbird species,
including several threatened species298.
The index of abundance for waterbirds in
eastern Australia has shown a declining
trend over past decades, with 2007 having
the second lowest abundance on record.
The declining abundance coincides with
declining habitat availability, which is
currently the lowest in 25 years.
The southern-most survey bands (bands
1-3) traverse Victoria and also extend from
the Coorong in South Australia across to
the NSW south coast. The abundance of
waterbirds in these bands shows wide
variability rather than an obvious declining
trend (see Figure IW5.6). This may reflect
the concentration of waterbirds close to
available water, as habitat further afield in
central NSW and southern Queensland
has been severely reduced.
A Victorian survey, the Summer Waterfowl
count, has monitored 300 wetlands
across Victoria since 1987 (see Figure
IW5.7). Survey results show a declining
trend in game duck numbers due to the
decreasing availability of wetland habitat.
A total of 91,210 game ducks were
counted in 2007, compared to 182,487
in 2006 and just 41% of the long-term
average of 219,465300.
Pressures
Alteration of habitat is a major pressure
for aquatic fauna and a primary cause of
decreasing native fish populations302. A
number of pressures on aquatic fauna are
listed as potentially threatening processes
under the Flora and Fauna Guarantee Act
1988. Processes relevant to freshwater
systems are listed below.
Flow regimes
Flow regimes and the pressure they place
on freshwater systems are discussed in
IW1 Flow regimes, with implications for
Aquatic Fauna discussed in IW1 Flow
regimes, Implications.
Degradation of in-stream habitat
In-stream habitat and the pressure that
its degradation places on freshwater
systems are discussed in IW2 In-stream
and wetland habitat, with implications
for Aquatic Fauna discussed in IW2 Instream
and wetland habitat, Implications.
Removal of wood debris from Victorian
streams, and prevention of passage of
aquatic biota as a result of the presence
of in-stream structures are both listed as
potentially threatening processes under
the Act.
Degraded riparian vegetation
Riparian vegetation and the pressures
that its degradation places on freshwater
systems are discussed in IW3 Riparian
vegetation, with implications for Aquatic
Fauna discussed in IW3 Riparian
vegetation, Implications.
Degraded water quality
Sediment input into rivers and streams
due to human activities is listed as a
potentially threatening Process under
the Act, as are two other forms of water
pollution:
• Input of toxic substances into Victorian
rivers and streams. Herbicides, for
example, have been implicated in a
number of fish kills, and emerging
scientific evidence points to their role in
the decline in amphibian populations.303
• Alteration to the natural temperature
regimes of rivers and streams. Water
released from dams, including water
released to generate hydro-electricity,
may be significantly colder than the
surface water, particularly during
summer304. This form of pollution is
pronounced downstream of the Hume,
Eildon, Thomson and Dartmouth
Dams, and a further 49 dams may be
implicated305.
Introduced species
Introduction of live fish into waters outside
their natural range within a Victorian
river catchment after 1770 is listed as a
potentially threatening process under the
Act. Introduced species and translocated
native species place pressure on
native aquatic fauna through predation,
competition, aggressive behaviour,
disease and habitat modification. Humans
have played a major role in the dispersal
of exotic freshwater species in Victoria306
for recreational fishing, ornamental
purposes and biological control, while
translocation of native species has been
used for aquaculture and to enhance
recreational fishing.
Recreational fishing and hunting
Recreational fishing and hunting exert a
small but localised pressure on aquatic
fauna through removal of fish and
waterbirds, bank erosion and associated
trampling of riparian and aquatic
vegetation. Over the past 13 years, the
duck hunting season has been cancelled
due to low bird numbers or breeding
activity in 1995, 2003, 2007 and 2008.
Climate change
Many of Victoria’s freshwater systems
are sensitive to climate variations307 and
climate change will be a major pressure
on aquatic fauna over the next few
decades308 (see IW6 Impacts of Climate
Change on Inland Waters for more detail).
Disease
Infection of amphibians with chytrid
fungus, resulting in chytridiomycosis
is listed as a key threatening process
under the Environment Protection and
Biodiversity Conservation Act 1999 (Cwlth)
and the Flora and Fauna Guarantee Act.
This fungus is known to affect the critically
endangered spotted tree frog309.
Implications
Ecosystems are generally very dynamic,
but recent research indicates that, if
certain tolerance thresholds are exceeded
for some species, their resilience will
be lost and ecosystems may change
irreversibly310. If keystone species such
as Murray cod are lost, this regime
change can prove even more dramatic
as cascading changes in ecosystem
structure and function take effect.
Generally, the presence of a number of
freshwater species with similar ecosystem
functions but different responses to
catchment modification may enhance the
resilience of ecosystems311. A diversity
of ecological responses to threats and
pressures helps to insure ecosystems
against the disturbances produced by
climate change.
Reduced survival and diversity of species
In those systems affected by river
regulation, fewer fish are able to
breed, fewer fish survive to adulthood
and, eventually, fewer fish species
survive312. For example, the highlyregulated
Campaspe River supports
significantly fewer native fish species
than the less-regulated Broken River.
The most-regulated upper sections of
the Campaspe River support far fewer
species and much lower abundances of
fish larvae because river regulation has
reduced habitat availability and quality313.
Furthermore, modification of seasonal
patterns of flow eliminates natural triggers
for migration and spawning in native fish
and affects the survival of juvenile fish.
Reduced flooding and increased river
regulation has led to reduced waterbird
breeding. Where river regulation and
diversions upstream have caused a
significant long-term decline in river
flows, waterbird abundance and diversity
has declined significantly over the
corresponding period314.
Removal of large woody habitat in northern
Victoria has added to the fragmentation
and reduction in Murray cod populations.
Reduction of in-stream woody habitat
has created large stretches of waterways
in Victoria unsuitable for Murray cod.
Its poor conservation status is largely
attributed to this factor315. Murray cod are
highly territorial, and prefer submerged
wood habitat for spawning and shelter.
Up to 80% of these fish are found within
a metre of a snag. Furthermore, Murray
cod, and freshwater blackfish, are known
to lay adhesive eggs on or in logs316.
Sedimentation, along with trout and redfin
predation, has also been an important
contributor to the decline of fish species
such as the Macquarie perch (Macquaria
australasica) in Victoria317.
The implications of degraded water quality
on aquatic fauna are presented in IW4
Water Quality, Implications.
The major implication of cold water
releases from dams is the direct loss
of species such as Murray cod, trout
cod, Macquarie perch, golden perch
(Macquaria Ambigua) and silver perch
from affected reaches318. Following the
construction of the Dartmouth Dam in
1980, populations of trout cod, Macquarie
perch and Murray cod were lost from
the Mitta Mitta River, due to cold water
releases inhibiting spawning and favouring
the introduced brown trout319.
Poor water quality can result in mass
deaths of fish and other aquatic fauna.
Three major incidents involving large
Murray cod in Victoria were reported
between 2002 and 2004. One of these
events, on Broken Creek in November
2002, resulted in the death of over 179
adult Murray cod320 and another event
in the Goulburn River in January 2004
resulted in the death of several thousand
fish321. Suggested causes included
low dissolved oxygen, high levels of
suspended sediment, and sudden
changes in temperature and herbicide
inputs322.
In 2006–07, seven fish death incidents
were reported in north-western Victoria,
with all but two incidents involving less
than 50 fish323. Likely causes included high
temperatures, low dissolved oxygen and
low flow.
Poor water quality can also have major
impacts on populations of aquatic
fauna. Large, mature fish take a long
time to replace. It was estimated that a
replacement program with an 80% chance
of restoring the Murray cod lost in either
the Broken Creek or Goulburn River fish
kills would cost approximately $1.5 million
and take about 30 years324.
While much smaller than the trout
species, the aggressive gambusia has
been implicated in the decline of at least
nine of species of fish and the decline of
more than 10 frog species in Australia325.
Gambusia chase and fin-nip fish much
larger than themselves prey on the eggs of
native fish and frogs and larval native fish
and significantly reduce growth rates of
small native fish326.
The impacts of carp on native fish
communities are not clear but their high
abundance in many streams and lakes
indicates they are probably competing
with native fish for food and space327. Their
feeding behaviour is a concern because
it may alter zooplankton levels, increase
turbidity and bank instability, and even
increase the risk of algal blooms328.
The distribution and abundance of native
galaxiid species in south-eastern Australia,
such as mountain galaxias (Galaxias
olidus) and barred galaxias (Galaxias
brevipinnis), have been seriously reduced
wherever brown trout and rainbow
trout have been introduced329. These
large predatory fish are also thought to
impact on a number of threatened frog
species such as the spotted tree frog
(Litoria spenceri)330. The spotted tree
frog has also been adversely affected by
sedimentation331.
Toxicological studies have shown the
high sensitivity of frogs to a wide range of
contaminants present in the surrounding
environment, due to their semi-permeable
skin332. At exposure to low concentrations
of contaminants, normal patterns of
growth can be altered333, resulting in
abnormalities of the limbs. Trace amounts
(0.1 parts per billion) of the herbicide
atrazine, Australia’s second most
commonly used agricultural pesticide,
have been found to cause male frogs
to grow ovaries334. Simazine, a related
herbicide, was found to have similar
effects.
Reduced ecosystem function and
ecosystem services
Loss of aquatic fauna can have cascading
effects on the conditions of inland waters.
For example, research has shown that
depletion of freshwater macro-invertebrate
diversity due to predation by brown trout
can influence nutrient spirallingxv and
decrease water quality. Predation by
this introduced species on algal grazers
such as freshwater molluscs has been
shown to increase the risk of algal blooms
downstream335.
Climate change will have serious
repercussions for aquatic fauna and
ecosystem services. Primarily, climate
change will affect aquatic fauna through
changes to rainfall and flow regimes,
altering the availability and quality of their
habitat. Climate change will also impact
aquatic fauna by altering the nature and
intensity of the existing pressures. For
many aquatic species already vulnerable,
the risk of local and broader extinctions
will increase and northern species, such
as spangled grunter (Leiopotherapon
unicolor) and an introduced cichlid fish,
tilapia, may be able to move south.
One tilapia species has established a
population in the warm water storages
of the Hazelwood power station near
Morwell336.
Extinction of aquatic fauna due to climate
change will impair the ability of inland
waters to provide ecosystem function
and reduce ecosystem stability and
recovery potential in a rapidly changing
environment. As a consequence, capacity
to generate ecosystem services will be
reduced337.
Recommendation
IW5.2 The Victorian Government,
in conjunction with other State and
Commonweatlh Governments, improve
knowledge and information regarding
resilience and thresholds for species,
communities and ecosystems in
respect of water quality, reduced flow
and invasive species.
Management responses
Aquatic fauna face numerous pressures,
as reported throughout this section.
Management responses must maintain
and improve habitat which supports
ecological communities as well as cater
for species-specific needs. Some of the
management responses of most benefit
to aquatic fauna are improvements to
in-stream habitat, riparian vegetation,
water quality and consistent provision of
worthwhile environmental flows, described
in the preceding sections.
The Murray-Darling Basin Council’s
Native Fish Strategy (2003–2013) outlines
responses to major pressures to fish
populations in the Murray-Darling Basin.
The Flora and Fauna Guarantee Act 1988
is failing to meet its stated objectives
and is in need of review (see Part 4.2:
Land and Biodiversity, LB3, Management
Responses). The Environment Protection
and Biodiversity Conservation Act 1999
(Cwlth) is also reported in Part 4.2: Land
and Biodiversity, LB3, Management
Responses.
Response Name
Guidelines for Assessing Translocations
of Live Aquatic Organisms in Victoria
Responsible Authority
Department of Primary Industries,
Department of Sustainability and
Environment
Response type
Guidelines
These guidelines provide a framework
for the assessment of proposals to
translocate live aquatic organisms within
and into Victoria, which require approval
under the Victorian Fisheries Act 1995338.
Translocation is the deliberate, humanassisted
movement of aquatic organisms
using associated transport media339. The
scope of these guidelines includes the
stocking of introduced species such as
trout for recreational fishing, as well as the
stocking of native fish for both recreational
fishing and conservation. Standard
protocols have been developed for the
most common types of translocation.
Accidental movement of aquatic
organisms is dealt with by other legislative
and administrative arrangements.
Recommendation
IW5.3 The Victorian Government should
develop a State action plan for exotic
aquatic species.
Response Name
Native Fish Restocking Program
Responsible Authority
Department of Primary Industries
Response type
Recovery program
Native fish populations have been
augmented by stocking of fingerlings
since 1988340, and this currently occurs
under the Guidelines for Assessing
Translocations of Live Aquatic Organisms
in Victoria (see Table IW5.1). The
purpose of stocking is to support
recreational fishing and maintain native
fish populations. However, stocking of
trout cod, which is considered critically
endangered under the Advisory list is
specifically for conservation341. Murray
cod, golden perch, silver perch and trout
cod are stocked into inland waters north of
the Divide. Australian bass, which is native
to coastal streams south of the Divide and
east of Wilson’s Promontory, are stocked
into selected lakes in this region.
While restocking programs contribute
significant numbers of juvenile fish, the
proportion of overall fish populations
resulting from restocking has not been
ascertained. Large, mature fish lost
through poor water quality events are not
easily replaced by restocking programs,
despite the large numbers of fingerlings
stocked (see IW5 Aquatic Fauna,
Implications).
Recommendation
IW5.4 The Victorian Government should
incorporate all native fish stocking into
population rehabilitation plans.
Evaluation of responses to
aquatic fauna
In addition to the measures described
above and in previous sections, there are
many other management responses to
pressures on aquatic fauna.
Through the Murray-Darling Basin
Council’s Native Fish Strategy
(2003–2013), fish passage is also
being improved along the main stem
of the River Murray, which should help
support fish populations in Victorian
tributaries. In 2001, the Murray-Darling
Basin Commission initiated a program to
improve fish passage from the sea to the
Hume Dam, a distance of over 2,000 km.
Fourteen fishways have been constructed
and monitoring suggests that they are
passing large numbers of fish (>50,000
fish over 40 days) with a high diversity of
species (13 species) and a wide range of
sizes (40 mm to 1,000 mm long)343.
Environmental water has been vital in
maintaining minimum standards of water
quality to support aquatic fauna in recent
years. The Lake Eildon water quality
reserve has been used several times to
improve Murray cod habitat in Broken
Creek, and water was also released to
maintain habitat for the Murray hardyhead
(Craterocephalus fluviatilis) in spring 2007.
Controversy surrounding the second
release (despite the relatively small volume
of water (1.6 GL) required) demonstrates
the pressures that are brought to bear on
environmental water managers.
Under the Flora and Fauna Guarantee Act,
action statements have been developed
for some threatened species, including
nine fish species, four amphibian species
and a number of waterbird species.
Recovery plans have also been developed
for some species of fish. Development
and implementation of these recovery
plans and action statements to allow longterm
restoration and management of these
populations would assist the conservation
of these species. Long-term, statewide
surveys of populations, such as the State
Waterfowl count and the fish surveys
described in Section 6.4 are important
management tools that deserve ongoing
funding.
For further information
Fishes of the Murray-Darling Basin
http://publication.mdbc.gov.au/index.php
Recommendations
IW5.5 Recovery plans for threatened
species should be implemented
systematically, for the long-term benefit
of the species
IW6 Impacts of Climate Change on Inland Waters
Key findings
• By 2030, streamflow may vary from
no change or slight increases in East
Gippsland to 25-40% decreases in river
systems in western and north-western
Victoria. By 2070, streamflow may
decrease by up to 50% across much of
the State.
• A rise in temperature of 1°C in the
Murray-Darling Basin reduces the
annual climatological inflow by 15%,
even if rainfall does not change.
• By 2020, a 10-40% reduction in
snow cover is likely with potentially
significant consequences for alpine and
downstream inland waters in Victoria.
Under a medium climate change
scenario, frequency of significant floods
in the Barmah forest will be once in 17
years. River red gums require significant
flooding every five to 10 years, which
means that without intervention, these
trees are unlikely to survive.
• Forest regrowth following more frequent
bushfires will be associated with heavy
uptake of water by the young trees at
the same time as predicted reductions
in rainfall. This will have a significant
impact on streamflow.
• The current degraded state of many
inland waters increases the challenge of
mitigating the environmental impacts of
climate change.
• In the northern region, most of the
water allocated to the environment is
in the components of flow that will be
most impacted by climate change; and
thus potentially may no longer be able
to meet the intended environmental
objectives.
Description
Current projections indicate that Victoria’s
future climate is likely to be warmer and,
for most of the State, drier than during the
second half of the twentieth century344 (see
Part 4.1: Atmosphere, Climate Change).
With lower water availability across most
of Victoria, streamflow and recharge of
groundwater are likely to decrease and
soil moisture will reduce.
Victoria is heavily dependent on surface
water availability, with 84% of water
harvested for consumption in 2006–07
coming from surface water sources. The
decade of low streamflow has highlighted
the vulnerability of domestic and rural
supply systems to prolonged reductions in its availability.
Lower streamflow increases the impact
of consumption on flow regimes, which
are already degraded in many rivers
(see IW1 Flow regimes). With climate
change, competition for water resources
is likely to increase, and the decisions
made to determine how Victoria’s water is
allocated, and the level of environmental
degradation that may result, will be
a major consideration as the costs
associated with maintaining healthy inland
waters rise.
The implications of climate change for
specific ecological communities are
not well understood. The effects are
expected to be varied and complex, but
generalisations are possible. Inland waters
are already degraded, and are under
ongoing pressure from human activities.
Climate change is an additional pressure
on Victoria’s degraded inland waters.
The impact of climate change will depend
on the rate at which it occurs, and the
extent to which the frequency of extreme
events changes. If the magnitude or
rate of climate change is outside the
range of past variations and exceeds the
capacity for species to migrate or adapt,
the vulnerability of inland waters will
increase345.
Climate change will also exacerbate other
pressures which may cumulatively reduce
water availability such as the loss of
connectivity of rivers, forests regenerating
after bushfires, the legacy of historic
groundwater extraction, and increased
interception of catchment runoff due to
forestry activities, farm dams and salt
interception schemes.
The purpose of this section is to identify
the impacts of climate change for Victorian
inland waters.
Objectives
• Improve decision support systems to
mitigate the impacts of climate change
on inland waters
• Identify, protect and restore inland
waters and, in particular, drought refugia
crucial for supporting biodiversity and
ecosystem resilience
• Improve the management of rivers and
wetlands during drought
• Manage catchments and riparian zones
to minimise the risk of extreme events
such as bushfires and flooding to inland
waters
State
The current state of Victoria’s climate
and projections for climate change are
examined in detail in Part 4.1: Atmosphere,
Climate Change.
Pressures
The key pressures arising from climate
change for inland waters are described
in Part 4.1: Atmosphere. In summary,
these include: uncertain changes in
rainfall but drier conditions are more likely
for most of the State; significant rises in
average annual temperature, especially for
overnight minimums; greater frequency of
extreme weather events such as severe
storms and floods; greater frequency and
intensity of forest fires; sea level rise; and
diminished snow cover and duration.
The impact of these pressures on inland
waters is closely linked to the impact of
these pressures on catchments, which
are discussed in Part 4.2: Land and
Biodiversity.
Implications
Reduced water availability
The major implication of climate change
for inland waters is the likelihood of
reduced water availability across most of
into rivers decreases by approximately
two to three per cent for every one per
cent decrease in rainfall 346.
By 2030, streamflow may vary from no change
or slight increases in East Gippsland to
25% to 40% decreases in river systems in
western and north-western Victoria (see
Figure IW6.1) 347
By 2070, streamflow may decrease by up to 50%. However, the
evidence to date suggests that climate
change is progressing more strongly than
that described in the highest scenario
used by the Intergovernmental Panel
on Climate Change 348. In rivers where
flow is not regulated by dams and weirs,
reduction in flow is likely to be greater
during winter, when rainfall decreases
are predicted to be larger 349. Less rainfall
and higher evaporation will also reduce
groundwater recharge, resulting in lower
watertables.
Victoria has already experienced a
Decade of low streamflow (see Part 3.2:
Water Resources) which, in many rivers,
particularly in the northern and central
areas, has generally been greater than
in the ‘high’ climate change scenario
for 2030350. It is not clear whether the
reduction in streamflows over the past
decade is due to climate change, but
climate change has been implicated in
the step changes to streamflow recorded
over the past four decades in southwestern
Western Australia. Many of the
weather systems that bring rain to south
west Western Australia also bring rain to
Victoria, although the reduction in rainfall
mechanisms to those reducing rainfall in
Victoria 351.
Temperatures are likely to increase under
climate change. There is evidence that
rising temperatures have had a strong
impact on the water resources of southern
Australia353. Historical data from the period
1950 to 2006 show that a rise of 1°C in
the Murray-Darling Basin leads to an
approximate 15% reduction in the annual
not change 354.
Evaporative losses in storages, which
are already considerable, will also
increase (see Part 3.2: Water Resources).
Reduced rainfall and lower soil moisture
caused by higher rates of evaporation
will increase the demand for irrigation
water355. These factors are all likely to
increase competition for available water.
Seasonal and intermittent waterbodies will
resilience of ecosystems.
Flow regimes
During years of low streamflow, the flow
to support environmental function in many
rivers reduces disproportionately, due to
competition with water consumption. For
example, a 35% reduction in the total flow
in the Upper Murray basin in 2004–05,
compared to annual average flows,
resulted in a 76% decrease in the volume
of water available for the environment (see
Part 3.2 Water Resources). Under climate
to support environmental function will
therefore be proportionately less than
that shown in Figure IW6.1, unless there
are changes to water allocations. The
condition of flow regimes, which is already
poor across many basins in Victoria, will
therefore decline even further.
The effects on components of the flow
regime are also important. The Northern
Region Sustainable Water Strategy
discussion paper provides examples of
the impacts of climate change on the high
and cease-to-flow components of flow
regimes in northern rivers. Flood frequency
reduces with higher climate change
scenarios. Even under a medium climate
change scenario, with current patterns
of water consumption, the gap between
significant floods in the Barmah forest
will be at least 17 years. Red Red Gum
forests require significant flooding every
five to ten years356, which means these
trees are unlikely to survive357. With tens
of thousands of hectares of forests and
wetlands already at risk of being lost, the
River Red Gum forests face a bleak future
without decisive intervention. Species
such as egrets, herons, spoonbills, and
Murray cod also depend on the flooding
of floodplains and riverine wetlands
for suitable breeding habitat, and their
continued survival will also be affected by
the reduced frequency of flooding358.
Reduced water availability also increases
the length of cease-to-flow events. The
Loddon River has ceased to flow for
longer than two months only twice in the
past 114 years–in 2004 and 2005359. If the
inflow patterns of the past decade are
applied to the 114-year historic record,
there are about 20 cease-to-flow events
longer than two months360. This change
could lead to the disappearance of the
regionally important river blackfish361.
The environmental water reserve, which is
the environment’s right to water, consists
of several different components within
the allocation framework. In the northern
region, only a very small percentage of
the environmental water reserve has high
reliability, and most of the water allocated
to the environment is in the components of
flow that will be most impacted by climate
change. The environmental water reserve
can be qualified for consumptive use
by ministerial discretion to meet critical
human need. In 2006/2007 there were 40
temporary reductions in the environmental
water reserve across the State to maintain
water supplies for human consumption.
With increased competition for water
resources into the future, the allocation
system must be sufficiently robust to deal
with water scarcity, and give equal status
to the environment’s right to water.
Across Victoria, flow regimes are most
altered from their natural condition in
summer, and the most altered component
during this time is low flow (see IW1 Flow
regimes). Under climate change, further
reductions in low-flow levels may occur
due to reduced groundwater recharge
or the effects of consumption discussed
above. Changes to the catchment, such
as the channelisation of streams and
wetlands and urbanisation, are likely to
enhance this tendency, as they result in
water moving more quickly through the
catchment. The implications of degraded
flow regimes are explained in IW1 Flow
regimes, Implications. During the decade
to 2005/06, autumn rains generally failed,
decreasing by 61%362. If this proves to be
a feature of rainfall patterns under climate
change, then it is likely the low flow period
in summer will lengthen, increasing the
stress on streams.
Furthermore, higher temperatures since
the 1950s have reduced the snow season
in the Australian Alps, leading to more
precipitation falling as rain rather than
snow, and earlier melting of snow on the
ground363. By 2020, a 10-40% reduction
in snow cover is likely364, resulting in
earlier peak autumn and winter flows, and
possibly higher peak flows365.
The predicted increase in the frequency
of bushfires may result in short-term
increases in streamflow366, followed by
longer-term reductions. Once regenerating
forest reaches a phase of rapid growth,
which may take 10 to 15 years367, it
uses more water than mature forest. It
is estimated that regrowth of vegetation
following the 2003 alpine fires will reduce
flows to the River Murray by up to 700 GL
a year or 10% of mean annual flow368. The
maximum reduction in flow is expected to
occur 20 to 25 years after the fire369, with
impacts continuing for another 80 to 100
years after that time370.
Reduced groundwater recharge has
the potential to decrease low-flow levels
in streams, and lower water levels in
wetlands. As a result, patterns of wetland
inundation may change, and seasonal
wetlands may become ephemeral. On the
other hand, reduced levels of groundwater
recharge may assist the control of
salinisation. Lower groundwater levels may
stress riparian and wetland vegetation that
is dependent on groundwater.
Rising sea levels may increase inundation
of coastal wetlands and floodplains, and
the length of estuarine reaches of rivers
will increase.
Biodiversity
Inland waters and their biodiversity have
been degraded and subject to numerous
pressures. Climate change will exacerbate
the impacts of many of these pressures on
biodiversity.
The frequency of disturbances to inland
waters, such as droughts and bushfires,
are likely to become more frequent. While
aquatic communities are adapted to
these natural disturbances, they depend
on having adequate refugia, and time
between disturbances, in which to recover.
Refuges can be provided by intact riparian
vegetation, as well as pools in rivers.
When flow returns, or following a bushfire,
populations can disperse and re-colonise
the rejuvenated landscape. Due to the
fragmentation and degradation of inland
waters however, many of these refuges
are damaged or inaccessible. Populations
fragmented by barriers, such as the river
blackfish in the Loddon River, or those with
low mobility, such as freshwater mussels
and crayfish, may be particularly affected
by the increasing lack of suitable habitat
during droughts.
Following the 2003 alpine fires, 30% of
sites monitored in an EPA study of fireaffected
areas in eastern Victoria showed
declines in stream health after the fires, as
measured by macro-invertebrates rather
than by an Index of Stream Condition
assessment. In most cases the streams
recovered to pre-fire levels of health
within three years. The recovery of native
fish populations may be more affected
by fragmentation due to barriers and
predation by rainbow and brown trout, and
therefore may be slower.
As noted in IW5 Aquatic Fauna,
Implications, a loss of resilience among
key species can irreversibly alter an
ecosystem’s structure and function 371.
Local extinction of freshwater fauna
species due to climate change impacts
will not only impair the ability of freshwater
ecosystems to provide ecosystem
functions but, by reducing biodiversity,
will also threaten system stability and
recovery potential in the rapidly changing
environment.
Recommendations
IW6.1 The Victorian Government should
consider listing climate change as a
threatening process under the Flora and
Fauna Guarantee Act 1988.
IW6.2 Identify drought refugia and
ensure adequate protection and
improvement of sites during drought.
IW6.3 Provision of adequate EWRs for
all rivers should receive priority over the
provision of drought refugia.
Water quality
Climate change will modify existing
pressures on water quality. Victoria
has experienced higher temperatures
over past decades leading to higher
water temperature. Temperature is a
controlling variable for the distribution of
many species of aquatic fauna, and will
have implications for the distributions of
sensitive species. Changing temperature
regimes will interact with other pressures,
such as the fragmentation of populations,
to dictate species’ distributions. These
implications may be mixed in the sense
that the distribution of invasive species like
trout, as well as those of native species,
may be limited.
Higher temperatures reduce the capacity
of water bodies to store dissolved oxygen,
and may increase the tendency to thermal
stratification in stationary water bodies
such as dams and weir pools. Combined
with lower inflow rates and higher rates
of plant respiration, this may increase
the frequency of low dissolved oxygen
concentrations. Over the 2007/2008
summer for example, there were several
occasions where water had to be released
along Broken Creek to increase dissolved
oxygen concentrations and avert Murray
Cod deaths372. Smaller volumes of water
present under low flow conditions are
also susceptible to larger variations in
water temperature, in particular from high
summer temperatures. Water bodies
under pressure from high nutrient levels
or modified flow regimes, such as weir
pools, will be particularly susceptible. As a
result algal blooms are likely to increase in
frequency373.
Reduced levels of groundwater recharge
may assist the control of salinisation374
but, higher rates of evaporation may lead
to high concentrations of salts and other
pollutants in surface waters.
The occurrence of fire events is likely to
increase. These can lead to both short
and long term effects on stream health
and water quality, including sedimentation
and algal blooms, due to nutrients bound
to the sediment375.
Climate change may also result in
acidification of inland waters, through
the exposure of acid sulfate soils to
oxygen376. In an undisturbed state, below
the water table or covered by surface
water, acid sulfate soils are benign
and not acidic. Exposure to oxygen
can occur through drying of surface
water, lowering of groundwater tables
through lack of recharge, excessive
extraction or dewatering processes, or
excavation. This triggers chemical and
micro-biological reactions that generate
significant amounts of sulfuric acid,
which can be extremely damaging to the
environment. Acidification of wetlands due
to excessive groundwater extraction and
reduced recharge has occurred along the
Swan Coastal Plain near Perth, Western
Australia377.
Recommendations
IW6.4 Identify areas most at risk of
in-stream habitat loss or degradation
due to climate change impacts and
incorporate these into regional river
health strategies.
IW6.5 Increase the knowledge and
understanding of the impacts of climate
change on the environmental values of
inland waters; including risks posed by
acidification.
Management responses
Climate change presents a major
challenge to water resources planning
because it will reduce water availability.
The current degraded state of many
inland waters increases the challenge
of mitigating the environmental impacts
of climate change. Developing the
knowledge and tools to analyse and plan
proactively, given the risks and uncertainty
associated with a changing climate, is a
high priority of water sector responses to
climate change.
Management responses to climate change
are also reported in Part 4.1: Atmosphere,
Climate Change.
Response Name
Estimation of water availability, MurrayDarling Basin Sustainable Yields Project
Responsible Authority
CSIRO
Response type
Model
The CSIRO has been contracted by the
National Water Commission to report on
current and future water availability in the
Murray-Darling Basin. This contract, which
was initiated in 2006 for completion in
2008, is the largest in CSIRO’s history378.
A computer model of the Murray-Darling
Basin’s water resources has been
developed that simulates surface water
and groundwater flows and extractions
within the basin’s catchments and the
interactions between the catchments.
The model simulates multiple climate
scenarios: the historical record, the past
10 years, a range (dry, medium and wet)
of possible climates by 2030, and takes
account of the influences of forestry, farm
dams and groundwater extraction379. In
all, over 600 permutations have been
simulated380. This information can be
used to assess the basin-wide impacts
of management decisions in any one part
of the basin, with greater confidence and
rigour than previously possible.
Current and future water availability for the
18 regions of the Murray-Darling Basin
has been finalised. Assessments of the
environmental requirements of inland
waters are not directly addressed in these
reports. While decisions about sustainable
yields, and who gets the water, should be
informed by the best available science,
they also require community input and
political deliberation.
Response Name
South Eastern Australian Climate
Initiative
Responsible Authority
Murray-Darling Basin Commission,
in collaboration with Department of
Sustainability and Environment, The
Australian Greenhouse Office (within
the Department of the Environment and
Water Resources), Australia’s Managing
Climate Variability program, CSIRO and
Bureau of Meteorology.
Response type
Research program
The South Eastern Australian Climate
Initiative (SEACI) is a $7 million, threeyear
program to investigate causes
and impacts of climate change and
climate variability across south-eastern
Australia381. The initiative commenced in
2006 and the research has three main
themes382:
• Assess the current level of knowledge
about climate variability and its drivers
over south-eastern Australia
• High-resolution climate projections
and impacts to determine the extent to
which climate in south-eastern Australia
are likely to change under enhanced
greenhouse conditions (changes in
average climate, inter-annual variability
and extreme events, and associated
impacts on streamflows)
Investigate whether reliable climate
forecasts with a lead time of three to 12
months can be applied to south-eastern
Australia, and if they can be applied to
crop forecasts and streamflows.
Evaluation of responses to the impacts of
climate change on inland waters
Inland waters are an integral part of the
landscape, and as the climate changes,
may become even more important
as refugia and links between different
bio-regions. It is therefore important
that the commitment to restore river
condition stated in Our Water Our Future is
maintained.
Understanding of the impact of climate
change on the water sector is developing
rapidly, and is being assimilated into
long-term planning. This is illustrative
of how quickly water resource planning
is changing (see Part 3.2: Water
Resources, Management Responses).
The assumptions used in these strategies
recognise that climate change may
result in ‘step changes’ to streamflow.
As pointed out in IW1 Flow Regimes,
Implications, the return of environmental
entitlements in the Northern region
are dependent on ‘normal’ rainfall and
implementation of entitlements for the
Central region have been delayed until
water storages recover383. This policy
appears inconsistent with current
projections for climate change and
appears to undermine the purpose of the
environmental water reserve.
Pressures outlined in earlier sections
reduce the capacity of inland waters
to resist and recover from events such
as drought which are likely to become
more common as the climate changes.
Management responses such as the
improvement of riparian vegetation
and connectivity of habitat proactively
minimise the impacts of drought384. Thus,
management responses outlined in earlier
sections may also play important roles in
adapting to a changing climate.
The implications of climate change for
specific ecological communities are not
well understood, nor are potential changes
in distribution of key aquatic fauna. As
a first step, catchment management
authorities have identified drought refuges
as a feature of drought response plans385.
These refuges could be given high priority
in the allocation of environmental water.
Difficult decisions will need to be made
in future as the availability of water
declines. Under severe climate change,
further trade-off of environmental assets
may be considered. If this occurs,
acknowledgement must be given to
the implicit trade-offs that have already
occurred through the development and
modification of inland waters.
The decisions are ultimately social and
therefore political choices. The processes
by which these are made can and must
be improved. Decision making must be
evidence based, transparent, equitable
and grounded in the understanding that
healthy communities ultimately depend
on a healthy environment. The greater the
‘water literacy’ and climate awareness
of the broader community, the greater
the prospect of the difficult long-term
decisions that the government needs to
make being more widely understood and
accepted by the community.
For further information
Sustainable Yields Project reports
http://www.csiro.au/partnerships/MDBSY.
html
Northern Region Sustainable Water
Strategy Discussion Paper
http://www.ourwater.vic.gov.au/programs/
sws/northern/strategy
Risks to the Shared Water Resources of
the Murray Darling Basin
http://www.clw.csiro.au/forms/pubslist/
Default.aspx?au=van%20dijk,%20
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